NFExpression.mo

/*
 * This file is part of OpenModelica.
 *
 * Copyright (c) 1998-2014, Open Source Modelica Consortium (OSMC),
 * c/o Linköpings universitet, Department of Computer and Information Science,
 * SE-58183 Linköping, Sweden.
 *
 * All rights reserved.
 *
 * THIS PROGRAM IS PROVIDED UNDER THE TERMS OF GPL VERSION 3 LICENSE OR
 * THIS OSMC PUBLIC LICENSE (OSMC-PL) VERSION 1.2.
 * ANY USE, REPRODUCTION OR DISTRIBUTION OF THIS PROGRAM CONSTITUTES
 * RECIPIENT'S ACCEPTANCE OF THE OSMC PUBLIC LICENSE OR THE GPL VERSION 3,
 * ACCORDING TO RECIPIENTS CHOICE.
 *
 * The OpenModelica software and the Open Source Modelica
 * Consortium (OSMC) Public License (OSMC-PL) are obtained
 * from OSMC, either from the above address,
 * from the URLs: http://www.ida.liu.se/projects/OpenModelica or
 * http://www.openmodelica.org, and in the OpenModelica distribution.
 * GNU version 3 is obtained from: http://www.gnu.org/copyleft/gpl.html.
 *
 * This program is distributed WITHOUT ANY WARRANTY; without
 * even the implied warranty of  MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE, EXCEPT AS EXPRESSLY SET FORTH
 * IN THE BY RECIPIENT SELECTED SUBSIDIARY LICENSE CONDITIONS OF OSMC-PL.
 *
 * See the full OSMC Public License conditions for more details.
 *
 */

encapsulated uniontype NFExpression
protected
  import Array;
  import Util;
  import Absyn;
  import AbsynUtil;
  import List;
  import System;
  import Flags;

  import Builtin = NFBuiltin;
  import BuiltinCall = NFBuiltinCall;
  import Expression = NFExpression;
  import Function = NFFunction;
  import NFPrefixes.{Variability, Purity};
  import Prefixes = NFPrefixes;
  import Ceval = NFCeval;
  import ComplexType = NFComplexType;
  import ExpandExp = NFExpandExp;
  import TypeCheck = NFTypeCheck;
  import ValuesUtil;
  import MetaModelica.Dangerous.*;
  import RangeIterator = NFRangeIterator;
  import JSON;

public
  import Absyn.Path;
  import DAE;
  import NFInstNode.InstNode;
  import Operator = NFOperator;
  import Subscript = NFSubscript;
  import Dimension = NFDimension;
  import Type = NFType;
  import ComponentRef = NFComponentRef;
  import Call = NFCall;
  import Binding = NFBinding;
  import NFClassTree.ClassTree;
  import Class = NFClass;
  import NFComponentRef.Origin;
  import Values;
  import Record = NFRecord;
  import ClockKind = NFClockKind;
  import ExpressionIterator = NFExpressionIterator;
  import InstContext = NFInstContext;
  import UnorderedMap;

  record INTEGER
    Integer value;
  end INTEGER;

  record REAL
    Real value;
  end REAL;

  record STRING
    String value;
  end STRING;

  record BOOLEAN
    Boolean value;
  end BOOLEAN;

  record ENUM_LITERAL
    Type ty;
    String name;
    Integer index;
  end ENUM_LITERAL;

  record CLKCONST "Clock constructors"
    ClockKind clk "Clock kinds";
  end CLKCONST;

  record CREF
    Type ty;
    ComponentRef cref;
  end CREF;

  record TYPENAME "Represents a type used as a range, e.g. Boolean."
    Type ty;
  end TYPENAME;

  record ARRAY
    Type ty;
    array<Expression> elements;
    Boolean literal "True if the array is known to only contain literal expressions.";
  end ARRAY;

  record MATRIX "The array concatentation operator [a,b; c,d]; this should be removed during type-checking"
    // Does not have a type since we only keep this operator before type-checking
    list<list<Expression>> elements;
  end MATRIX;

  record RANGE
    Type ty;
    Expression start;
    Option<Expression> step;
    Expression stop;
  end RANGE;

  record TUPLE
    Type ty;
    list<Expression> elements;
  end TUPLE;

  record RECORD
    Path path; // Maybe not needed since the type contains the name. Prefix?
    Type ty;
    list<Expression> elements;
  end RECORD;

  record CALL
    Call call;
  end CALL;

  record SIZE
    Expression exp;
    Option<Expression> dimIndex;
  end SIZE;

  record END
  end END;

  record BINARY "Binary operations, e.g. a+4"
    Expression exp1;
    Operator operator;
    Expression exp2;
  end BINARY;

  record UNARY "Unary operations, -(4x)"
    Operator operator;
    Expression exp;
  end UNARY;

  record LBINARY "Logical binary operations: and, or"
    Expression exp1;
    Operator operator;
    Expression exp2;
  end LBINARY;

  record LUNARY "Logical unary operations: not"
    Operator operator;
    Expression exp;
  end LUNARY;

  record RELATION "Relation, e.g. a <= 0"
    Expression exp1;
    Operator operator;
    Expression exp2;
  end RELATION;

  record MULTARY
    "Multary expressions with the same operator, e.g. a+b+c
    An empty list has to be interpreted as the neutral element of the operator space"
    list<Expression> arguments      "arguments that are chained with the operator (+, *)";
    list<Expression> inv_arguments  "arguments that are chained with the inverse operator (-, :)";
    Operator operator               "Can only be + or * (commutative)";
  end MULTARY;

  record IF
    Type ty;
    Expression condition;
    Expression trueBranch;
    Expression falseBranch;
  end IF;

  record CAST
    Type ty;
    Expression exp;
  end CAST;

  record BOX "MetaModelica boxed value"
    Expression exp;
  end BOX;

  record UNBOX "MetaModelica value unboxing (similar to a cast)"
    Expression exp;
    Type ty;
  end UNBOX;

  record SUBSCRIPTED_EXP
    Expression exp;
    list<Subscript> subscripts;
    Type ty;
    Boolean split;
  end SUBSCRIPTED_EXP;

  record TUPLE_ELEMENT
    Expression tupleExp;
    Integer index;
    Type ty;
  end TUPLE_ELEMENT;

  record RECORD_ELEMENT
    Expression recordExp;
    Integer index;
    String fieldName;
    Type ty;
  end RECORD_ELEMENT;

  record MUTABLE
    Mutable<Expression> exp;
  end MUTABLE;

  record EMPTY
    Type ty;
  end EMPTY;

  record PARTIAL_FUNCTION_APPLICATION
    ComponentRef fn;
    list<Expression> args;
    list<String> argNames;
    Type ty;
  end PARTIAL_FUNCTION_APPLICATION;

  record FILENAME
    String filename;
  end FILENAME;

  function isArray
    input Expression exp;
    output Boolean isArray;
  algorithm
    isArray := match exp
      case ARRAY() then true;
      else false;
    end match;
  end isArray;

  function isEmptyArray
    input Expression exp;
    output Boolean emptyArray;
  algorithm
    emptyArray := match exp
      case ARRAY() then arrayEmpty(exp.elements);
      else false;
    end match;
  end isEmptyArray;

  function isVector
    input Expression exp;
    output Boolean res;
  algorithm
    res := match exp
      case ARRAY() then Type.isVector(exp.ty);
      else false;
    end match;
  end isVector;

  function isCref
    input Expression exp;
    output Boolean isCref;
  algorithm
    isCref := match exp
      case CREF() then true;
      else false;
    end match;
  end isCref;

  function isFunctionInputCref
    input Expression exp;
    output Boolean res;
  algorithm
    res := match exp
      case CREF() then ComponentRef.isInput(ComponentRef.last(exp.cref));
      else false;
    end match;
  end isFunctionInputCref;

  function isWildCref
    input Expression exp;
    output Boolean wild;
  algorithm
    wild := match exp
      case CREF(cref = ComponentRef.WILD()) then true;
      else false;
    end match;
  end isWildCref;

  function isCall
    input Expression exp;
    output Boolean isCall;
  algorithm
    isCall := match exp
      case CALL() then true;
      else false;
    end match;
  end isCall;

  function isImpureCall
    input Expression exp;
    output Boolean isImpure;
  algorithm
    isImpure := match exp
      case CALL() then Call.isImpure(exp.call);
      else false;
    end match;
  end isImpureCall;

  function isExternalCall
    input Expression exp;
    output Boolean res;
  algorithm
    res := match exp
      case CALL() then Call.isExternal(exp.call);
      else false;
    end match;
  end isExternalCall;

  function isCallNamed
    input Expression exp;
    input String name;
    output Boolean res;
  algorithm
    res := match exp
      case CALL() then Call.isNamed(exp.call, name);
      else false;
    end match;
  end isCallNamed;

  function isTrue
    input Expression exp;
    output Boolean isTrue;
  algorithm
    isTrue := match exp
      case BOOLEAN(true) then true;
      else false;
    end match;
  end isTrue;

  function isAllTrue
    input Expression exp;
    output Boolean isTrue;
  algorithm
    isTrue := match exp
      local
        Expression e;
      case BOOLEAN(true) then true;
      case ARRAY() then Array.all(exp.elements, isAllTrue);
      case CALL(call = Call.TYPED_ARRAY_CONSTRUCTOR(exp = e)) then Expression.isAllTrue(e);
      else false;
    end match;
  end isAllTrue;

  function isFalse
    input Expression exp;
    output Boolean isTrue;
  algorithm
    isTrue := match exp
      case BOOLEAN(false) then true;
      else false;
    end match;
  end isFalse;

  function isTrivialCref
    input Expression exp;
    output Boolean b;
  algorithm
    b := match exp
      case Expression.CREF() then true;
      case Expression.UNARY(exp = Expression.CREF()) then true;
      case Expression.LUNARY(exp = Expression.CREF()) then true;
      else false;
    end match;
  end isTrivialCref;

  function isEqual
    "Returns true if the two expressions are equal, otherwise false."
    input Expression exp1;
    input Expression exp2;
    output Boolean isEqual;
  algorithm
    isEqual := 0 == compare(exp1, exp2);
  end isEqual;

  function compare
    "Checks whether two expressions are equal, and returns 0 if they are.
     If the first expression is 'less' than the second it returns an integer
     less than 0, otherwise an integer greater than 0."
    input Expression exp1;
    input Expression exp2;
    output Integer comp;
  algorithm
    // Check if the expressions are the same object.
    if referenceEq(exp1, exp2) then
      comp := 0;
      return;
    end if;

    // Return false if the expressions are of different kinds.
    comp := Util.intCompare(valueConstructor(exp1), valueConstructor(exp2));
    if comp <> 0 then
      return;
    end if;

    comp := match (exp1)
      local
        Integer i;
        Real r;
        String s;
        Boolean b;
        ComponentRef cr;
        Type ty;
        list<Expression> expl, inv_expl;
        Expression e1, e2, e3;
        Option<Expression> oe;
        Path p;
        Operator op;
        Call c;
        list<Subscript> subs;
        ClockKind clk1, clk2;
        Mutable<Expression> me;
        list<list<Expression>> mat;
        array<Expression> arr;

      case INTEGER()
        algorithm
          INTEGER(value = i) := exp2;
        then
          Util.intCompare(exp1.value, i);

      case REAL()
        algorithm
          REAL(value = r) := exp2;
        then
          Util.realCompare(exp1.value, r);

      case STRING()
        algorithm
          STRING(value = s) := exp2;
        then
          Util.stringCompare(exp1.value, s);

      case BOOLEAN()
        algorithm
          BOOLEAN(value = b) := exp2;
        then
          Util.boolCompare(exp1.value, b);

      case ENUM_LITERAL()
        algorithm
          ENUM_LITERAL(ty = ty, index = i) := exp2;
          comp := AbsynUtil.pathCompare(Type.enumName(exp1.ty), Type.enumName(ty));

          if comp == 0 then
            comp := Util.intCompare(exp1.index, i);
          end if;
        then
          comp;

      case CLKCONST(clk1)
        algorithm
          CLKCONST(clk2) := exp2;
        then
          ClockKind.compare(clk1, clk2);

      case CREF()
        algorithm
          CREF(cref = cr) := exp2;
        then
          ComponentRef.compare(exp1.cref, cr);

      case TYPENAME()
        algorithm
          TYPENAME(ty = ty) := exp2;
        then
          valueCompare(exp1.ty, ty);

      case ARRAY()
        algorithm
          ARRAY(ty = ty, elements = arr) := exp2;
          comp := valueCompare(ty, exp1.ty);
        then
          if comp == 0 then Array.compare(exp1.elements, arr, compare) else comp;

      case MATRIX()
        algorithm
          MATRIX(elements = mat) := exp2;
        then
          List.compare(exp1.elements, mat, function List.compare(compareFn = compare));

      case RANGE()
        algorithm
          RANGE(start = e1, step = oe, stop = e2) := exp2;
          comp := compare(exp1.start, e1);
          if comp == 0 then
            comp := compare(exp1.stop, e2);
            if comp == 0 then
              comp := compareOpt(exp1.step, oe);
            end if;
          end if;
        then
          comp;

      case TUPLE()
        algorithm
          TUPLE(elements = expl) := exp2;
        then
          List.compare(exp1.elements, expl, compare);

      case RECORD()
        algorithm
          RECORD(path = p, elements = expl) := exp2;
          comp := AbsynUtil.pathCompare(exp1.path, p);
        then
          if comp == 0 then List.compare(exp1.elements, expl, compare) else comp;

      case CALL()
        algorithm
          CALL(call = c) := exp2;
        then
          Call.compare(exp1.call, c);

      case SIZE()
        algorithm
          SIZE(exp = e1, dimIndex = oe) := exp2;
          comp := compareOpt(exp1.dimIndex, oe);
        then
          if comp == 0 then compare(exp1.exp, e1) else comp;

      case END() then 0;

      case MULTARY()
        algorithm
          MULTARY(arguments = expl, inv_arguments = inv_expl, operator = op) := exp2;
          comp := Operator.compare(exp1.operator, op);
          if comp == 0 then
            comp := compareList(exp1.arguments, expl);
          end if;
          if comp == 0 then
            comp := compareList(exp1.inv_arguments, inv_expl);
          end if;
        then
          comp;

      case BINARY()
        algorithm
          BINARY(exp1 = e1, operator = op, exp2 = e2) := exp2;
          comp := Operator.compare(exp1.operator, op);
          if comp == 0 then
            comp := compare(exp1.exp1, e1);
            if comp == 0 then
              comp := compare(exp1.exp2, e2);
            end if;
          end if;
        then
          comp;

      case UNARY()
        algorithm
          UNARY(operator = op, exp = e1) := exp2;
          comp := Operator.compare(exp1.operator, op);
        then
          if comp == 0 then compare(exp1.exp, e1) else comp;

      case LBINARY()
        algorithm
          LBINARY(exp1 = e1, operator = op, exp2 = e2) := exp2;
          comp := Operator.compare(exp1.operator, op);
          if comp == 0 then
            comp := compare(exp1.exp1, e1);
            if comp == 0 then
              comp := compare(exp1.exp2, e2);
            end if;
          end if;
        then
          comp;

      case LUNARY()
        algorithm
          LUNARY(operator = op, exp = e1) := exp2;
          comp := Operator.compare(exp1.operator, op);
        then
          if comp == 0 then compare(exp1.exp, e1) else comp;

      case RELATION()
        algorithm
          RELATION(exp1 = e1, operator = op, exp2 = e2) := exp2;
          comp := Operator.compare(exp1.operator, op);
          if comp == 0 then
            comp := compare(exp1.exp1, e1);
            if comp == 0 then
              comp := compare(exp1.exp2, e2);
            end if;
          end if;
        then
          comp;

      case IF()
        algorithm
          IF(condition = e1, trueBranch = e2, falseBranch = e3) := exp2;
          comp := compare(exp1.condition, e1);
          if comp == 0 then
            comp := compare(exp1.trueBranch, e2);
            if comp == 0 then
              comp := compare(exp1.falseBranch, e3);
            end if;
          end if;
        then
          comp;

      case CAST()
        algorithm
          e1 := match exp2
                  case CAST(exp = e1) then e1;
                  case e1 then e1;
                end match;
        then
          compare(exp1.exp, e1);

      case BOX()
        algorithm
          BOX(exp = e2) := exp2;
        then
          compare(exp1.exp, e2);

      case UNBOX()
        algorithm
          UNBOX(exp = e1) := exp2;
        then
          compare(exp1.exp, e1);

      case SUBSCRIPTED_EXP()
        algorithm
          SUBSCRIPTED_EXP(exp = e1, subscripts = subs) := exp2;
          comp := compare(exp1.exp, e1);

          if comp == 0 then
            comp := Subscript.compareList(exp1.subscripts, subs);
          end if;
        then
          comp;

      case TUPLE_ELEMENT()
        algorithm
          TUPLE_ELEMENT(tupleExp = e1, index = i) := exp2;
          comp := Util.intCompare(exp1.index, i);

          if comp == 0 then
            comp := compare(exp1.tupleExp, e1);
          end if;
        then
          comp;

      case RECORD_ELEMENT()
        algorithm
          RECORD_ELEMENT(recordExp = e1, index = i) := exp2;
          comp := Util.intCompare(exp1.index, i);

          if comp == 0 then
            comp := compare(exp1.recordExp, e1);
          end if;
        then
          comp;

      case MUTABLE()
        algorithm
          MUTABLE(exp = me) := exp2;
        then
          compare(Mutable.access(exp1.exp), Mutable.access(me));

      case EMPTY()
        algorithm
          EMPTY(ty = ty) := exp2;
        then
          valueCompare(exp1.ty, ty);

      case PARTIAL_FUNCTION_APPLICATION()
        algorithm
          PARTIAL_FUNCTION_APPLICATION(fn = cr, args = expl) := exp2;
          comp := ComponentRef.compare(exp1.fn, cr);

          if comp == 0 then
            comp := List.compare(exp1.args, expl, compare);
          end if;
        then
          comp;

      case FILENAME()
        algorithm
          FILENAME(filename = s) := exp2;
        then
          Util.stringCompare(exp1.filename, s);

      else
        algorithm
          Error.assertion(false, getInstanceName() + " got unknown expression.", sourceInfo());
        then
          fail();

    end match;
  end compare;

  function compareOpt
    input Option<Expression> expl1;
    input Option<Expression> expl2;
    output Integer comp;
  protected
    Expression e1, e2;
  algorithm
    comp := match(expl1, expl2)
      case (NONE(), NONE()) then 0;
      case (NONE(), _) then -1;
      case (_, NONE()) then 1;
      case (SOME(e1), SOME(e2)) then compare(e1, e2);
    end match;
  end compareOpt;

  function compareList
    input list<Expression> expl1;
    input list<Expression> expl2;
    output Integer comp = List.compare(expl1, expl2, compare);
  end compareList;

  function typeOf
    input Expression exp;
    output Type ty;
  algorithm
    ty := match exp
      case INTEGER()         then Type.INTEGER();
      case REAL()            then Type.REAL();
      case STRING()          then Type.STRING();
      case BOOLEAN()         then Type.BOOLEAN();
      case ENUM_LITERAL()    then exp.ty;
      case CLKCONST()        then Type.CLOCK();
      case CREF()            then exp.ty;
      case TYPENAME()        then exp.ty;
      case ARRAY()           then exp.ty;
      case RANGE()           then exp.ty;
      case TUPLE()           then exp.ty;
      case RECORD()          then exp.ty;
      case CALL()            then Call.typeOf(exp.call);
      case SIZE()            then if isSome(exp.dimIndex) then
                                    Type.INTEGER() else Type.sizeType(typeOf(exp.exp));
      case END()             then Type.INTEGER();
      case MULTARY()         then Operator.typeOf(exp.operator);
      case BINARY()          then Operator.typeOf(exp.operator);
      case UNARY()           then Operator.typeOf(exp.operator);
      case LBINARY()         then Operator.typeOf(exp.operator);
      case LUNARY()          then Operator.typeOf(exp.operator);
      case RELATION()        then Type.copyDims(Operator.typeOf(exp.operator), Type.BOOLEAN());
      case IF()              then exp.ty;
      case CAST()            then exp.ty;
      case BOX()             then Type.METABOXED(typeOf(exp.exp));
      case UNBOX()           then exp.ty;
      case SUBSCRIPTED_EXP() then exp.ty;
      case TUPLE_ELEMENT()   then exp.ty;
      case RECORD_ELEMENT()  then exp.ty;
      case MUTABLE()         then typeOf(Mutable.access(exp.exp));
      case EMPTY()           then exp.ty;
      case PARTIAL_FUNCTION_APPLICATION() then exp.ty;
      case FILENAME()        then Type.STRING();
      else Type.UNKNOWN();
    end match;
  end typeOf;

  function setType
    input Type ty;
    input output Expression exp;
  algorithm
    exp := match exp
      case ENUM_LITERAL()    algorithm exp.ty := ty; then exp;
      case CREF()            algorithm exp.ty := ty; then exp;
      case TYPENAME()        algorithm exp.ty := ty; then exp;
      case ARRAY()           algorithm exp.ty := ty; then exp;
      case RANGE()           algorithm exp.ty := ty; then exp;
      case TUPLE()           algorithm exp.ty := ty; then exp;
      case RECORD()          algorithm exp.ty := ty; then exp;
      case CALL()            algorithm exp.call := Call.setType(exp.call, ty); then exp;
      case BINARY()          algorithm exp.operator := Operator.setType(ty, exp.operator); then exp;
      case UNARY()           algorithm exp.operator := Operator.setType(ty, exp.operator); then exp;
      case LBINARY()         algorithm exp.operator := Operator.setType(ty, exp.operator); then exp;
      case LUNARY()          algorithm exp.operator := Operator.setType(ty, exp.operator); then exp;
      case RELATION()        algorithm exp.operator := Operator.setType(ty, exp.operator); then exp;
      case IF()              algorithm exp.ty := ty; then exp;
      case CAST()            algorithm exp.ty := ty; then exp;
      case UNBOX()           algorithm exp.ty := ty; then exp;
      case SUBSCRIPTED_EXP() algorithm exp.ty := ty; then exp;
      case TUPLE_ELEMENT()   algorithm exp.ty := ty; then exp;
      case RECORD_ELEMENT()  algorithm exp.ty := ty; then exp;
      case PARTIAL_FUNCTION_APPLICATION() algorithm exp.ty := ty; then exp;
      else exp;
    end match;
  end setType;

  function typeCastOpt
    input Option<Expression> exp;
    input Type ty;
    output Option<Expression> outExp = Util.applyOption(exp, function typeCast(ty = ty));
  end typeCastOpt;

  function typeCast
    "Converts an expression to the given type. Dimensions of array types can be
     omitted, and are ignored by this function, since arrays can't be cast to a
     different size. Only the element type of the type is used, so for example:
       typeCast({1, 2, 3}, Type.REAL()) => {1.0, 2.0, 3.0}

     The function does not check that the cast is valid, and expressions that
     can't be converted outright will be wrapped as a CAST expression."
    input output Expression exp;
    input Type ty;
  protected
    Type t, t2, ety;
    list<Expression> el;
    Expression e1, e2;
    Integer dim_diff;
    array<Expression> arr;
  algorithm
    ety := Type.arrayElementType(ty);

    exp := match exp
      // Integer can be cast to Real.
      case INTEGER()
        then if Type.isReal(ety) then REAL(intReal(exp.value))
             elseif Type.isEnumeration(ety) and Flags.isConfigFlagSet(Flags.ALLOW_NON_STANDARD_MODELICA, "nonStdIntegersAsEnumeration") // Integer can be cast to Enumeration with non-standard Modelica
             then ENUM_LITERAL(ety, Type.nthEnumLiteral(ety, exp.value), exp.value)
             else typeCastGeneric(exp, ety);

      // Enumeration can be cast to Integer with non-standard Modelica
      case ENUM_LITERAL() guard Flags.isConfigFlagSet(Flags.ALLOW_NON_STANDARD_MODELICA, "nonStdEnumerationAsIntegers")
        then if Type.isInteger(ety) then INTEGER(toInteger(exp)) else typeCastGeneric(exp, ety);

      // Boolean can be cast to Real (only if -d=nfAPI is on)
      // as there are annotations having expressions such as Boolean x > 0.5
      case BOOLEAN()
        then if Type.isReal(ety) and Flags.isSet(Flags.NF_API) then
          REAL(if exp.value then 1.0 else 0.0) else typeCastGeneric(exp, ety);

      // Real doesn't need to be cast to Real, since we convert e.g. array with
      // a mix of Integers and Reals to only Reals.
      case REAL()
        then if Type.isReal(ety) then exp else typeCastGeneric(exp, ety);

      // For arrays we typecast each element and update the type of the array.
      case ARRAY(ty = t, elements = arr)
        algorithm
          arr := Array.map(arr, function typeCast(ty = ety));
          t := Type.setArrayElementType(t, ety);
        then
          makeArray(t, arr, exp.literal);

      case RANGE(ty = t)
        algorithm
          t := Type.setArrayElementType(t, ety);
        then
          RANGE(t, typeCast(exp.start, ety), typeCastOpt(exp.step, ety), typeCast(exp.stop, ety));

      // Unary operators (i.e. -) are handled by casting the operand.
      case UNARY()
        algorithm
          t := Type.setArrayElementType(Operator.typeOf(exp.operator), ety);
        then
          UNARY(Operator.setType(t, exp.operator), typeCast(exp.exp, ety));

      // If-expressions are handled by casting each of the branches.
      case IF()
        algorithm
          e1 := typeCast(exp.trueBranch, ety);
          e2 := typeCast(exp.falseBranch, ety);
          t := if Type.isConditionalArray(ty) then
            Type.setConditionalArrayTypes(ty, typeOf(e1), typeOf(e2)) else typeOf(e1);
        then
          IF(t, exp.condition, e1, e2);

      // Calls are handled by Call.typeCast, which has special rules for some functions.
      case CALL()
        then Call.typeCast(exp, ety);

      // Casting a cast expression overrides its current cast type.
      case CAST() then typeCast(exp.exp, ty);

      case SUBSCRIPTED_EXP()
        algorithm
          e1 := typeCast(exp.exp, ety);
          t := Type.setArrayElementType(exp.ty, ety);
        then
          SUBSCRIPTED_EXP(e1, exp.subscripts, t, exp.split);

      // Other expressions are handled by making a CAST expression.
      else typeCastGeneric(exp, ety);
    end match;
  end typeCast;

  function typeCastGeneric
    input output Expression exp;
    input Type ty;
  protected
    Type exp_ty = typeOf(exp);
  algorithm
    if not Type.isEqual(ty, Type.arrayElementType(exp_ty)) then
      exp := CAST(Type.setArrayElementType(exp_ty, ty), exp);
    end if;
  end typeCastGeneric;

  function realValue
    input Expression exp;
    output Real value;
  algorithm
    value := match exp
      case REAL() then exp.value;
      case INTEGER() then intReal(exp.value);
    end match;
  end realValue;

  function makeReal
    input Real value;
    output Expression exp = REAL(value);
  end makeReal;

  function integerValue
    input Expression exp;
    output Integer value;
  algorithm
    INTEGER(value=value) := exp;
  end integerValue;

  function integerValueOrDefault
    input Expression exp;
    input output Integer value = 0;
  algorithm
    value := match exp
      case INTEGER() then exp.value;
      else value;
    end match;
  end integerValueOrDefault;

  function makeInteger
    input Integer value;
    output Expression exp = INTEGER(value);
  end makeInteger;

  function stringValue
    input Expression exp;
    output String value;
  algorithm
    value := match exp
      case STRING() then exp.value;
      case FILENAME() then exp.filename;
      else "";
    end match;
  end stringValue;

  function booleanValue
    input Expression exp;
    output Boolean value;
  algorithm
    try
      BOOLEAN(value=value) := exp;
    else
      value := false;
    end try;
  end booleanValue;

  function makeArray
    input Type ty;
    input array<Expression> expl;
    input Boolean literal = false;
    output Expression outExp;
  algorithm
    outExp := ARRAY(ty, expl, literal);
    annotation(__OpenModelica_EarlyInline = true);
  end makeArray;

  function makeArrayCheckLiteral
    input Type ty;
    input array<Expression> expl;
    output Expression outExp;
  algorithm
    outExp := ARRAY(ty, expl, Array.all(expl, isLiteral));
    annotation(__OpenModelica_EarlyInline = true);
  end makeArrayCheckLiteral;

  function makeEmptyArray
    input Type ty;
    output Expression outExp;
  algorithm
    outExp := ARRAY(ty, listArray({}), true);
    annotation(__OpenModelica_EarlyInline = true);
  end makeEmptyArray;

  function makeIntegerArray
    input list<Integer> values;
    output Expression exp;
  algorithm
    exp := makeArray(Type.ARRAY(Type.INTEGER(), {Dimension.fromInteger(listLength(values))}),
                     Array.mapList(values, makeInteger),
                     literal = true);
  end makeIntegerArray;

  function makeRealArray
    input list<Real> values;
    output Expression exp;
  algorithm
    exp := makeArray(Type.ARRAY(Type.REAL(), {Dimension.fromInteger(listLength(values))}),
                     Array.mapList(values, makeReal),
                     literal = true);
  end makeRealArray;

  function makeRealMatrix
    input list<list<Real>> values;
    output Expression exp;
  protected
    Type ty;
    list<Expression> expl;
  algorithm
    if listEmpty(values) then
      ty := Type.ARRAY(Type.REAL(), {Dimension.fromInteger(0), Dimension.UNKNOWN()});
      exp := makeEmptyArray(ty);
    else
      ty := Type.ARRAY(Type.REAL(), {Dimension.fromInteger(listLength(listHead(values)))});
      expl := list(makeArray(ty, listArray(list(REAL(v) for v in row)), literal = true) for row in values);
      ty := Type.liftArrayLeft(ty, Dimension.fromInteger(listLength(expl)));
      exp := makeArray(ty, listArray(expl), literal = true);
    end if;
  end makeRealMatrix;

  function makeExpArray
    input array<Expression> elements;
    input Type elementType;
    input Boolean isLiteral = false;
    output Expression exp;
  protected
    Type ty;
  algorithm
    ty := Type.liftArrayLeft(elementType, Dimension.fromInteger(arrayLength(elements)));
    exp := makeArray(ty, elements, isLiteral);
  end makeExpArray;

  function makeRecord
    input Absyn.Path recordName;
    input Type recordType;
    input list<Expression> fields;
    output Expression exp;
  algorithm
    exp := RECORD(recordName, recordType, fields);
  end makeRecord;

  function makeRange
    input Expression start;
    input Option<Expression> step;
    input Expression stop;
    output Expression rangeExp;
  algorithm
    rangeExp := RANGE(
      TypeCheck.getRangeType(start, step, stop, typeOf(start), AbsynUtil.dummyInfo),
      start, step, stop
    );
  end makeRange;

  function makeIntegerRange
    input Integer start;
    input Integer step;
    input Integer stop;
    output Expression rangeExp;
  protected
    Expression start_exp, stop_exp;
    Option<Expression> step_exp;
  algorithm
    start_exp := INTEGER(start);
    stop_exp := INTEGER(stop);

    if start == stop or
       step == 1 and start <= stop or
       step == -1 and start >= stop then
      step_exp := NONE();
    else
      step_exp := SOME(INTEGER(step));
    end if;

    rangeExp := makeRange(start_exp, step_exp, stop_exp);
  end makeIntegerRange;

  function getIntegerRange
    input Expression range  "has to be RANGE()!";
    output Integer start;
    output Integer step;
    output Integer stop;
  algorithm
    (start, step, stop) := match range
      local
        Option<Expression> step_opt;
      case RANGE(start = INTEGER(start), step = step_opt, stop = INTEGER(stop)) algorithm
        if Util.isSome(step_opt) then
          SOME(INTEGER(step)) := step_opt;
        else
          step := if start > stop then -1 else 1;
        end if;
      then (start, step, stop);
      else algorithm
        Error.assertion(false, getInstanceName() + " expression not RANGE(): " + toString(range), sourceInfo());
      then fail();
    end match;
  end getIntegerRange;

  function makeTuple
    input list<Expression> expl;
    output Expression tupleExp;
  protected
    list<Type> tyl;
  algorithm
    if listLength(expl) == 1 then
      tupleExp := listHead(expl);
    else
      tyl := list(typeOf(e) for e in expl);
      tupleExp := TUPLE(Type.TUPLE(tyl, NONE()), expl);
    end if;
  end makeTuple;

  function rangeSize
    input Expression range  "has to be RANGE()!";
    output Integer size = Dimension.size(Type.nthDimension(typeOf(range), 1));
  end rangeSize;

  function applySubscripts
    "Subscripts an expression with the given list of subscripts."
    input list<Subscript> subscripts;
    input Expression exp;
    output Expression outExp;
  algorithm
    if listEmpty(subscripts) then
      outExp := exp;
    else
      outExp := applySubscript(listHead(subscripts), exp, listRest(subscripts));
    end if;
  end applySubscripts;

  function applySubscript
    "Subscripts an expression with the given subscript, and then applies the
     optional list of subscripts to each element of the subscripted expression."
    input Subscript subscript;
    input Expression exp;
    input list<Subscript> restSubscripts = {};
    output Expression outExp;
  algorithm
    outExp := match exp
      case CREF() then applySubscriptCref(subscript, exp.cref, restSubscripts);

      case TYPENAME() guard listEmpty(restSubscripts)
        then applySubscriptTypename(subscript, exp.ty);

      case ARRAY() then applySubscriptArray(subscript, exp, restSubscripts);

      case RANGE() guard listEmpty(restSubscripts)
        then applySubscriptRange(subscript, exp);

      case CALL()
        then applySubscriptCall(subscript, exp, restSubscripts);

      case IF() then applySubscriptIf(subscript, exp, restSubscripts);

      case UNBOX()
        algorithm
          outExp := applySubscript(subscript, exp.exp, restSubscripts);
        then
          unbox(outExp);

      case BOX() then box(applySubscript(subscript, exp.exp, restSubscripts));

      case CAST()
        algorithm
          outExp := applySubscript(subscript, exp.exp, restSubscripts);
        then
          CAST(Type.copyElementType(typeOf(outExp), exp.ty), outExp);

      else makeSubscriptedExp(subscript :: restSubscripts, exp);
    end match;
  end applySubscript;

  function applySubscriptCref
    input Subscript subscript;
    input ComponentRef cref;
    input list<Subscript> restSubscripts;
    output Expression outExp;
  protected
    ComponentRef cr;
    Type ty;
  algorithm
    cr := ComponentRef.mergeSubscripts(subscript :: restSubscripts, cref);
    ty := ComponentRef.getSubscriptedType(cr);
    outExp := CREF(ty, cr);
  end applySubscriptCref;

  function applySubscriptTypename
    input Subscript subscript;
    input Type ty;
    output Expression outExp;
  protected
    Subscript sub;
    Integer index;
    array<Expression> expl;
  algorithm
    sub := Subscript.expandSlice(subscript);

    outExp := match sub
      case Subscript.INDEX() then applyIndexSubscriptTypename(ty, sub);

      case Subscript.SLICE()
        then SUBSCRIPTED_EXP(TYPENAME(ty), {subscript}, Type.ARRAY(ty, {Subscript.toDimension(sub)}), false);

      case Subscript.WHOLE()
        then TYPENAME(ty);

      case Subscript.EXPANDED_SLICE()
        algorithm
          expl := Array.mapList(sub.indices, function applyIndexSubscriptTypename(ty = ty));
        then
          makeArray(Type.liftArrayLeft(ty, Dimension.fromInteger(arrayLength(expl))), expl, literal = true);

    end match;
  end applySubscriptTypename;

  function applyIndexSubscriptTypename
    input Type ty;
    input Subscript index;
    output Expression subscriptedExp;
  protected
    Expression idx_exp;
    Integer idx;
  algorithm
    idx_exp := Subscript.toExp(index);

    if isScalarLiteral(idx_exp) then
      idx := toInteger(idx_exp);

      subscriptedExp := match ty
        case Type.BOOLEAN() guard idx <= 2
          then if idx == 1 then BOOLEAN(false) else BOOLEAN(true);

        case Type.ENUMERATION() then nthEnumLiteral(ty, idx);
      end match;
    else
      subscriptedExp := SUBSCRIPTED_EXP(TYPENAME(ty), {index}, ty, false);
    end if;
  end applyIndexSubscriptTypename;

  function applySubscriptArray
    input Subscript subscript;
    input Expression exp;
    input list<Subscript> restSubscripts;
    output Expression outExp;
  protected
    Subscript sub, s;
    list<Subscript> rest_subs;
    array<Expression> expl;
    Type ty;
    Integer el_count;
    Boolean literal;
    Expression first_e;
  algorithm
    if isEmptyArray(exp) then
      outExp := makeSubscriptedExp(subscript :: restSubscripts, exp);
      return;
    end if;

    sub := Subscript.expandSlice(subscript);

    outExp := match sub
      case Subscript.INDEX() then applyIndexSubscriptArray(exp, sub, restSubscripts);
      case Subscript.SLICE() then makeSubscriptedExp(subscript :: restSubscripts, exp);
      case Subscript.WHOLE()
        algorithm
          if listEmpty(restSubscripts) then
            outExp := exp;
          else
            ARRAY(ty = ty, elements = expl, literal = literal) := exp;
            s :: rest_subs := restSubscripts;
            expl := Array.map(expl, function applySubscript(subscript = s, restSubscripts = rest_subs));
            (ty, literal) := typeSubscriptedArray(expl, restSubscripts, ty, literal);
            outExp := makeArray(ty, expl, literal);
          end if;
        then
          outExp;

      case Subscript.EXPANDED_SLICE()
        algorithm
          ARRAY(ty = ty, literal = literal) := exp;
          expl := Array.mapList(sub.indices,
            function applyIndexSubscriptArray(exp = exp, restSubscripts = restSubscripts));
          (ty, literal) := typeSubscriptedArray(expl, restSubscripts, ty, literal);
        then
          makeArray(ty, expl, literal);

      case Subscript.SPLIT_INDEX() then makeSubscriptedExp(subscript :: restSubscripts, exp);

    end match;
  end applySubscriptArray;

  function typeSubscriptedArray
    input array<Expression> elements;
    input list<Subscript> subscripts;
    input output Type ty;
    input output Boolean literal;
  protected
    Integer count;
    Expression e;
  algorithm
    count := arrayLength(elements);

    if count > 0 then
      // If the array isn't empty, use the type of the first element.
      e := elements[1];
      ty := typeOf(e);
      // Non-literal subscripts might change an array from literal to non-literal.
      literal := literal and isLiteral(e);
    else
      // If the array is empty, use the slower method of subscripting the type.
      ty := Type.subscript(Type.unliftArray(ty), subscripts);
    end if;

    ty := Type.liftArrayLeft(ty, Dimension.fromInteger(count));
  end typeSubscriptedArray;

  function applyIndexSubscriptArray
    input Expression exp;
    input Subscript index;
    input list<Subscript> restSubscripts;
    output Expression outExp;
  algorithm
    outExp := applyIndexExpArray(exp, Subscript.toExp(index), restSubscripts);
  end applyIndexSubscriptArray;

  function applyIndexExpArray
    input Expression exp;
    input Expression index;
    input list<Subscript> restSubscripts;
    output Expression outExp;
  protected
    array<Expression> expl;
  algorithm
    if isScalarLiteral(index) then
      ARRAY(elements = expl) := exp;
      outExp := applySubscripts(restSubscripts, arrayGet(expl, toInteger(index)));
    else
      outExp := makeSubscriptedExp(Subscript.INDEX(index) :: restSubscripts, exp);
    end if;
  end applyIndexExpArray;

  function applySubscriptRange
    input Subscript subscript;
    input Expression exp;
    output Expression outExp;
  protected
    Subscript sub;
    Expression start_exp, stop_exp;
    Option<Expression> step_exp;
    Type ty;
    array<Expression> expl;
  algorithm
    sub := Subscript.expandSlice(subscript);

    outExp := match sub
      case Subscript.INDEX() then applyIndexSubscriptRange(exp, sub);

      case Subscript.SLICE()
        algorithm
          RANGE(ty = ty) := exp;
          ty := Type.ARRAY(Type.unliftArray(ty), {Subscript.toDimension(sub)});
        then
          SUBSCRIPTED_EXP(exp, {subscript}, ty, false);

      case Subscript.WHOLE() then exp;

      case Subscript.EXPANDED_SLICE()
        algorithm
          expl := Array.mapList(sub.indices, function applyIndexSubscriptRange(rangeExp = exp));
          RANGE(ty = ty) := exp;
        then
          makeArray(Type.liftArrayLeft(ty, Dimension.fromInteger(arrayLength(expl))), expl);

      case Subscript.SPLIT_INDEX()
        algorithm
          RANGE(ty = ty) := exp;
          ty := Type.unliftArray(ty);
        then
          SUBSCRIPTED_EXP(exp, {sub}, ty, true);

      else
        algorithm
          Error.assertion(false, getInstanceName() + " got unknown subscript '" + Subscript.toString(sub) + "'", sourceInfo());
        then
          fail();

    end match;
  end applySubscriptRange;

  function applyIndexSubscriptRange
    input Expression rangeExp;
    input Subscript index;
    output Expression outExp;
  protected
    Expression index_exp, start_exp, stop_exp;
    Option<Expression> step_exp;
    Type ty;
    list<Subscript> subs;
  algorithm
    Subscript.INDEX(index = index_exp) := index;

    if isScalarLiteral(index_exp) then
      RANGE(start = start_exp, step = step_exp, stop = stop_exp) := rangeExp;
      outExp := applyIndexSubscriptRange2(start_exp, step_exp, stop_exp, toInteger(index_exp));
    else
      RANGE(ty = ty) := rangeExp;
      subs := {index};
      ty := Type.subscript(ty, subs);
      outExp := SUBSCRIPTED_EXP(rangeExp, subs, ty, false);
    end if;
  end applyIndexSubscriptRange;

  function applyIndexSubscriptRange2
    input Expression startExp;
    input Option<Expression> stepExp;
    input Expression stopExp;
    input Integer index;
    output Expression subscriptedExp;
  protected
    Integer iidx;
    Real ridx;
  algorithm
    subscriptedExp := match (startExp, stepExp)
      case (INTEGER(), SOME(INTEGER(iidx)))
        then INTEGER(startExp.value + (index - 1) * iidx);

      case (INTEGER(), _)
        then INTEGER(startExp.value + index - 1);

      case (REAL(), SOME(REAL(ridx)))
        then REAL(startExp.value + (index - 1) * ridx);

      case (REAL(), _)
        then REAL(startExp.value + index - 1.0);

      case (BOOLEAN(), _)
        then if index == 1 then startExp else stopExp;

      case (ENUM_LITERAL(index = iidx), _)
        algorithm
          iidx := iidx + index - 1;
        then
          nthEnumLiteral(startExp.ty, iidx);

    end match;
  end applyIndexSubscriptRange2;

  function applySubscriptCall
    input Subscript subscript;
    input Expression exp;
    input list<Subscript> restSubscripts;
    output Expression outExp;
  protected
    Call call;
  algorithm
    CALL(call = call) := exp;

    outExp := match call
      local
        Expression arg;
        Type ty;

      case Call.TYPED_CALL(arguments = {arg})
        guard Function.Function.isSubscriptableBuiltin(call.fn)
        algorithm
          arg := applySubscript(subscript, arg, restSubscripts);
          ty := Type.copyDims(typeOf(arg), call.ty);
        then
          CALL(Call.TYPED_CALL(call.fn, ty, call.var, call.purity, {arg}, call.attributes));

      case Call.TYPED_ARRAY_CONSTRUCTOR()
        then applySubscriptArrayConstructor(subscript, call, restSubscripts);

      else makeSubscriptedExp(subscript :: restSubscripts, exp);
    end match;
  end applySubscriptCall;

  function applySubscriptArrayConstructor
    input Subscript subscript;
    input Call call;
    input list<Subscript> restSubscripts;
    output Expression outExp;
  algorithm
    if Subscript.isIndex(subscript) and listEmpty(restSubscripts) then
      outExp := applyIndexSubscriptArrayConstructor(call, subscript);
    else
      // TODO: Handle slicing and multiple subscripts better.
      outExp := makeSubscriptedExp(subscript :: restSubscripts, CALL(call));
    end if;
  end applySubscriptArrayConstructor;

  function applyIndexSubscriptArrayConstructor
    input Call call;
    input Subscript index;
    output Expression subscriptedExp;
  protected
    Type ty;
    Variability var;
    Purity pur;
    Expression exp, iter_exp;
    list<tuple<InstNode, Expression>> iters;
    InstNode iter;
  algorithm
    Call.TYPED_ARRAY_CONSTRUCTOR(ty, var, pur, exp, iters) := call;
    ((iter, iter_exp), iters) := List.splitLast(iters);
    iter_exp := applySubscript(index, iter_exp);
    subscriptedExp := replaceIterator(exp, iter, iter_exp);

    if not listEmpty(iters) then
      subscriptedExp := CALL(Call.TYPED_ARRAY_CONSTRUCTOR(Type.unliftArray(ty), var, pur, subscriptedExp, iters));
    end if;
  end applyIndexSubscriptArrayConstructor;

  function applySubscriptIf
    input Subscript subscript;
    input Expression exp;
    input list<Subscript> restSubscripts;
    output Expression outExp;
  protected
    Expression cond, tb, fb;
    Type ty;
  algorithm
    IF(ty, cond, tb, fb) := exp;

    if Type.isConditionalArray(ty) then
      // Subscripting both branches of a conditional array might not be possible
      // since they have different dimensions. If it fails just subscript the
      // whole if-expression instead.
      try
        tb := applySubscript(subscript, tb, restSubscripts);
        fb := applySubscript(subscript, fb, restSubscripts);
        ty := Type.setConditionalArrayTypes(ty, typeOf(tb), typeOf(fb));
        outExp := IF(ty, cond, tb, fb);
      else
        outExp := makeSubscriptedExp(subscript :: restSubscripts, exp);
      end try;
    else
      tb := applySubscript(subscript, tb, restSubscripts);
      fb := applySubscript(subscript, fb, restSubscripts);
      ty := typeOf(tb);
      outExp := IF(ty, cond, tb, fb);
    end if;
  end applySubscriptIf;

  function makeSubscriptedExp
    input list<Subscript> subscripts;
    input Expression exp;
    input Boolean backend = false;
    output Expression outExp;
  protected
    Expression e;
    list<Subscript> subs, extra_subs;
    Type ty;
    Integer dim_count;
    Boolean split;
  algorithm
    // If the expression is already a SUBSCRIPTED_EXP we need to concatenate the
    // old subscripts with the new. Otherwise we just create a new SUBSCRIPTED_EXP.
    (e, subs, ty, split) := match exp
      case SUBSCRIPTED_EXP() then (exp.exp, exp.subscripts, typeOf(exp.exp), exp.split);
      else (exp, {}, typeOf(exp), false);
    end match;

    if not split then
      split := List.exist(subscripts, Subscript.isSplitIndex);
    end if;

    dim_count := Type.dimensionCount(ty);
    (subs, extra_subs) := Subscript.mergeList(subscripts, subs, dim_count, backend);

    // Check that the expression has enough dimensions to be subscripted.
    if not listEmpty(extra_subs) then
      Error.assertion(false, getInstanceName() + ": too few dimensions in " +
        toString(exp) + " to apply subscripts " + Subscript.toStringList(subscripts), sourceInfo());
    end if;

    ty := Type.subscript(ty, subs);
    outExp := SUBSCRIPTED_EXP(e, subs, ty, split);
  end makeSubscriptedExp;

  function replaceIterator
    "Replaces the given iterator with the given value in an expression."
    input output Expression exp;
    input InstNode iterator;
    input Expression iteratorValue;
  algorithm
    exp := map(exp, function replaceIterator2(iterator = iterator, iteratorValue = iteratorValue));
  end replaceIterator;

  function replaceIterator2
    input Expression exp;
    input InstNode iterator;
    input Expression iteratorValue;
    output Expression outExp;
  algorithm
    outExp := match exp
      local
        InstNode node;
        ComponentRef cref;
        list<String> fields;

      // Cref is simple identifier, i
      case CREF(cref = ComponentRef.CREF(node = node))
        guard ComponentRef.isSimple(exp.cref)
        then if InstNode.refEqual(iterator, node) then iteratorValue else exp;

      // Cref is qualified identifier, i.x
      case CREF(cref = ComponentRef.CREF())
        algorithm
          // Only the first (last in stored order) part of a cref can be an iterator.
          node := ComponentRef.node(ComponentRef.last(exp.cref));

          if InstNode.refEqual(iterator, node) then
            // Start with the given value.
            outExp := iteratorValue;

            // Go down into the record fields using the rest of the cref.
            fields := list(InstNode.name(n) for n in listRest(ComponentRef.nodes(exp.cref)));

            for f in fields loop
              outExp := recordElement(f, outExp);
            end for;
          else
            outExp := exp;
          end if;
        then
          outExp;

      else exp;
    end match;
  end replaceIterator2;

  function containsIterator
    input Expression exp;
    input InstNode iterator;
    output Boolean res;
  protected
    function containsIterator2
      input Expression exp;
      input InstNode iterator;
      output Boolean res;
    algorithm
      res := match exp
        local
          InstNode node;

        case CREF(cref = ComponentRef.CREF(node = node))
          then InstNode.refEqual(node, iterator);
        else false;
      end match;
    end containsIterator2;
  algorithm
    res := contains(exp, function containsIterator2(iterator = iterator));
  end containsIterator;

  function arrayFromList
    input list<Expression> inExps;
    input Type elemTy;
    input list<Dimension> inDims;
    output Expression outExp;
  algorithm
    outExp := arrayFromList_impl(inExps, elemTy, listReverse(inDims));
  end arrayFromList;

  function arrayFromList_impl
    input list<Expression> inExps;
    input Type elemTy;
    input list<Dimension> inDims;
    output Expression outExp;
  protected
    Dimension ldim;
    list<Dimension> restdims;
    Type ty;
    list<Expression> newlst;
    list<list<Expression>> partexps;
    Integer dimsize;
  algorithm
    Error.assertion(not listEmpty(inDims), "Empty dimension list given in arrayFromList.", sourceInfo());

    ldim::restdims := inDims;
    dimsize := Dimension.size(ldim);
    ty := Type.liftArrayLeft(elemTy, ldim);

    if List.hasOneElement(inDims) then
      Error.assertion(dimsize == listLength(inExps), "Length mismatch in arrayFromList.", sourceInfo());
      outExp := makeArray(ty, listArray(inExps));
      return;
    end if;

    partexps := List.partition(inExps, dimsize);

    newlst := {};
    for arrexp in partexps loop
      newlst := makeArray(ty, listArray(arrexp))::newlst;
    end for;

    newlst := listReverse(newlst);
    outExp := arrayFromList_impl(newlst, ty, restdims);
  end arrayFromList_impl;

  function makeEnumLiteral
    input Type enumType;
    input Integer index;
    output Expression literal;
  protected
    list<String> literals;
  algorithm
    Type.ENUMERATION(literals = literals) := enumType;
    literal := ENUM_LITERAL(enumType, listGet(literals, index), index);
  end makeEnumLiteral;

  function makeEnumLiterals
    input Type enumType;
    output list<Expression> literals;
  protected
    list<String> lits;
  algorithm
    Type.ENUMERATION(literals = lits) := enumType;
    literals := list(ENUM_LITERAL(enumType, l, i)
      threaded for l in lits, i in 1:listLength(lits));
  end makeEnumLiterals;

  function toInteger
    input Expression exp;
    output Integer i;
  algorithm
    i := match exp
      case INTEGER() then exp.value;
      case BOOLEAN() then if exp.value then 2 else 1;
      case ENUM_LITERAL() then exp.index;
    end match;
  end toInteger;

  function toStringTyped
    input Expression exp;
    output String str;
  algorithm
    str := "/*" + Type.toString(typeOf(exp)) + "*/ " + toString(exp);
  end toStringTyped;

  function toString
    input Expression exp;
    output String str;
  protected
    Type t;
    ClockKind clk;
    Expression first, first_inv;
    list<Expression> rest, rest_inv;
  algorithm
    str := match exp
      case INTEGER() then intString(exp.value);
      case REAL() then realString(exp.value);
      case STRING() then "\"" + System.escapedString(exp.value, false) + "\"";
      case BOOLEAN() then boolString(exp.value);

      case ENUM_LITERAL(ty = t as Type.ENUMERATION())
        then AbsynUtil.pathString(t.typePath) + "." + exp.name;

      case CLKCONST(clk) then ClockKind.toString(clk);
      case CREF() then ComponentRef.toString(exp.cref);
      case TYPENAME() then Type.typenameString(Type.arrayElementType(exp.ty));
      case ARRAY() then "{" + stringDelimitList(list(toString(e) for e in exp.elements), ", ") + "}";
      case MATRIX() then "[" + stringDelimitList(list(stringDelimitList(list(toString(e) for e in el), ", ") for el in exp.elements), "; ") + "]";

      case RANGE() then operandString(exp.start, exp, false) +
                        (
                        if isSome(exp.step)
                        then ":" + operandString(Util.getOption(exp.step), exp, false)
                        else ""
                        ) + ":" + operandString(exp.stop, exp, false);

      case TUPLE() then "(" + stringDelimitList(list(toString(e) for e in exp.elements), ", ") + ")";
      case RECORD() then List.toString(exp.elements, toString, AbsynUtil.pathString(exp.path), "(", ", ", ")", true);
      case CALL() then Call.toString(exp.call);
      case SIZE() then "size(" + toString(exp.exp) +
                        (
                        if isSome(exp.dimIndex)
                        then ", " + toString(Util.getOption(exp.dimIndex))
                        else ""
                        ) + ")";
      case END() then "end";

      case MULTARY() guard(listEmpty(exp.inv_arguments)) then multaryString(exp.arguments, exp, exp.operator, false);

      case MULTARY() guard(listEmpty(exp.arguments) and Operator.isDashClassification(Operator.getMathClassification(exp.operator)))
                     then "-" + multaryString(exp.inv_arguments, exp, exp.operator);

      case MULTARY() guard(listEmpty(exp.arguments)) then "1/" + multaryString(exp.inv_arguments, exp, exp.operator);

      case MULTARY() then multaryString(exp.arguments, exp, exp.operator) +
                          Operator.symbol(Operator.invert(exp.operator)) +
                          multaryString(exp.inv_arguments, exp, exp.operator);

      case BINARY() then operandString(exp.exp1, exp, true) +
                         Operator.symbol(exp.operator) +
                         operandString(exp.exp2, exp, false);

      case UNARY() then Operator.symbol(exp.operator, "") +
                        operandString(exp.exp, exp, false);

      case LBINARY() then operandString(exp.exp1, exp, true) +
                          Operator.symbol(exp.operator) +
                          operandString(exp.exp2, exp, false);

      case LUNARY() then Operator.symbol(exp.operator, "") + " " +
                         operandString(exp.exp, exp, false);

      case RELATION() then operandString(exp.exp1, exp, true) +
                           Operator.symbol(exp.operator) +
                           operandString(exp.exp2, exp, false);

      case IF() then "if " + toString(exp.condition) + " then " + toString(exp.trueBranch) + " else " + toString(exp.falseBranch);

      case CAST() then if Flags.isSet(Flags.NF_API) then
                         toString(exp.exp)
                       else
                         "CAST(" + Type.toString(exp.ty) + ", " + toString(exp.exp) + ")";

      case BOX() then "BOX(" + toString(exp.exp) + ")";
      case UNBOX() then "UNBOX(" + toString(exp.exp) + ")";
      case SUBSCRIPTED_EXP() then "(" + toString(exp.exp) + ")" + Subscript.toStringList(exp.subscripts);
      case TUPLE_ELEMENT() then toString(exp.tupleExp) + "[" + intString(exp.index) + "]";
      case RECORD_ELEMENT() then toString(exp.recordExp) + "[field: " + exp.fieldName + "]";
      case MUTABLE() then toString(Mutable.access(exp.exp));
      case EMPTY() then "#EMPTY#";
      case PARTIAL_FUNCTION_APPLICATION()
        then "function " + ComponentRef.toString(exp.fn) + "(" + stringDelimitList(
          list(n + " = " + toString(a) threaded for a in exp.args, n in exp.argNames), ", ") + ")";

      case FILENAME() then "\"" + System.escapedString(exp.filename, false) + "\"";
      else anyString(exp);
    end match;
  end toString;

  function toFlatString
    input Expression exp;
    output String str;
  protected
    Type t;
    ClockKind clk;
    Expression first;
    list<Expression> rest;
  algorithm
    str := match exp
      case INTEGER() then intString(exp.value);
      case REAL() then realString(exp.value);
      case STRING() then "\"" + Util.escapeModelicaStringToCString(exp.value) + "\"";
      case BOOLEAN() then boolString(exp.value);

      case ENUM_LITERAL(ty = t as Type.ENUMERATION())
        then "'" + AbsynUtil.pathString(t.typePath) + "'." + exp.name;

      case CLKCONST(clk) then ClockKind.toFlatString(clk);

      case CREF() then ComponentRef.toFlatString(exp.cref);
      case TYPENAME() then Type.typenameString(Type.arrayElementType(exp.ty));

      case ARRAY()
        then if arrayEmpty(exp.elements) then
          "fill("+toFlatString(makeDefaultValue(Type.elementType(exp.ty)))+", " + Type.dimensionsToFlatString(exp.ty) + ")"
        else
          "{" + stringDelimitList(list(toFlatString(e) for e in exp.elements), ", ") + "}";

      case MATRIX() then "[" + stringDelimitList(list(stringDelimitList(list(toFlatString(e) for e in el), ", ") for el in exp.elements), "; ") + "]";

      case RANGE() then operandFlatString(exp.start, exp, false) +
                        (
                        if isSome(exp.step)
                        then ":" + operandFlatString(Util.getOption(exp.step), exp, false)
                        else ""
                        ) + ":" + operandFlatString(exp.stop, exp, false);

      case TUPLE() then "(" + stringDelimitList(list(toFlatString(e) for e in exp.elements), ", ") + ")";
      case RECORD() then List.toString(exp.elements, toFlatString, "'" + AbsynUtil.pathString(exp.path), "'(", ", ", ")", true);
      case CALL() then Call.toFlatString(exp.call);
      case SIZE() then "size(" + toFlatString(exp.exp) +
                        (
                        if isSome(exp.dimIndex)
                        then ", " + toFlatString(Util.getOption(exp.dimIndex))
                        else ""
                        ) + ")";
      case END() then "end";

      case MULTARY() guard(listEmpty(exp.inv_arguments)) then multaryFlatString(exp.arguments, exp, exp.operator, false);

      case MULTARY() guard(listEmpty(exp.arguments) and Operator.isDashClassification(Operator.getMathClassification(exp.operator)))
                     then "-" + multaryFlatString(exp.inv_arguments, exp, exp.operator);

      case MULTARY() guard(listEmpty(exp.arguments)) then "1/" + multaryFlatString(exp.inv_arguments, exp, exp.operator);

      case MULTARY() then multaryFlatString(exp.arguments, exp, exp.operator) +
                          Operator.symbol(Operator.invert(exp.operator)) +
                          multaryFlatString(exp.inv_arguments, exp, exp.operator);

      case BINARY() then operandFlatString(exp.exp1, exp, true) +
                         Operator.symbol(exp.operator) +
                         operandFlatString(exp.exp2, exp, false);

      case UNARY() then Operator.symbol(exp.operator, "") +
                        operandFlatString(exp.exp, exp, false);

      case LBINARY() then operandFlatString(exp.exp1, exp, true) +
                          Operator.symbol(exp.operator) +
                          operandFlatString(exp.exp2, exp, false);

      case LUNARY() then Operator.symbol(exp.operator, "") + " " +
                         operandFlatString(exp.exp, exp, false);

      case RELATION() then operandFlatString(exp.exp1, exp, true) +
                           Operator.symbol(exp.operator) +
                           operandFlatString(exp.exp2, exp, false);

      case IF() then "if " + toFlatString(exp.condition) + " then " + toFlatString(exp.trueBranch) + " else " + toFlatString(exp.falseBranch);

      case CAST() then toFlatString(exp.exp);
      case UNBOX() then "UNBOX(" + toFlatString(exp.exp) + ")";
      case BOX() then "BOX(" + toFlatString(exp.exp) + ")";

      case SUBSCRIPTED_EXP() then toFlatSubscriptedString(exp.exp, exp.subscripts);
      case TUPLE_ELEMENT() then toFlatString(exp.tupleExp) + "[" + intString(exp.index) + "]";
      case RECORD_ELEMENT() then toFlatString(exp.recordExp) + "[field: " + exp.fieldName + "]";
      case MUTABLE() then toFlatString(Mutable.access(exp.exp));
      case EMPTY() then "#EMPTY#";
      case PARTIAL_FUNCTION_APPLICATION()
        then "function " + ComponentRef.toFlatString(exp.fn) + "(" + stringDelimitList(
          list(n + " = " + toFlatString(a) threaded for a in exp.args, n in exp.argNames), ", ") + ")";

      case FILENAME() then "\"" + Util.escapeModelicaStringToCString(exp.filename) + "\"";
      else anyString(exp);
    end match;
  end toFlatString;

  function toFlatSubscriptedString
    input Expression exp;
    input list<Subscript> subscripts;
    output String str;
  protected
    Type exp_ty;
    list<Type> sub_tyl;
    list<Dimension> dims;
    list<String> strl;
    String name;
    list<Subscript> subs;
  algorithm
    if Flags.getConfigBool(Flags.MODELICA_OUTPUT) then
      subs := list(s for s guard not Subscript.isSplitIndex(s) in subscripts);

      if listEmpty(subs) then
        str := toFlatString(exp);
      else
        exp_ty := typeOf(exp);
        dims := List.firstN(Type.arrayDims(exp_ty), listLength(subs));
        sub_tyl := list(Dimension.subscriptType(d) for d in dims);
        name := Type.subscriptedTypeName(exp_ty, sub_tyl);

        strl := {")"};

        for s in subs loop
          strl := Subscript.toFlatString(s) :: strl;
          strl := "," :: strl;
        end for;

        strl := toFlatString(exp) :: strl;
        strl := "'(" :: strl;
        strl := name :: strl;
        strl := "'" :: strl;
        str := stringAppendList(strl);
      end if;
    else
      str := "(" + toFlatString(exp) + ")" + Subscript.toFlatStringList(subscripts);
    end if;
  end toFlatSubscriptedString;

  function operandString
    "Helper function to toString, prints an operator and adds parentheses as needed."
    input Expression operand;
    input Expression operator;
    input Boolean lhs;
    output String str;
  protected
    Integer operand_prio, operator_prio;
    Boolean parenthesize = false;
  algorithm
    str := toString(operand);
    operand_prio := priority(operand, lhs);

    if operand_prio == 4 then
      parenthesize := true;
    else
      operator_prio := priority(operator, lhs);

      if operand_prio > operator_prio then
        parenthesize := true;
      elseif operand_prio == operator_prio then
        parenthesize := if lhs then isNonAssociativeExp(operand) else not
                                    isAssociativeExp(operand);
      end if;
    end if;

    if parenthesize then
      str := "(" + str + ")";
    end if;
  end operandString;

  function operandFlatString
    "Helper function to toString, prints an operator and adds parentheses as needed."
    input Expression operand;
    input Expression operator;
    input Boolean lhs;
    output String str;
  protected
    Integer operand_prio, operator_prio;
    Boolean parenthesize = false;
  algorithm
    str := toFlatString(operand);
    operand_prio := priority(operand, lhs);

    if operand_prio == 4 then
      parenthesize := true;
    else
      operator_prio := priority(operator, lhs);

      if operand_prio > operator_prio then
        parenthesize := true;
      elseif operand_prio == operator_prio then
        parenthesize := if lhs then isNonAssociativeExp(operand)
                               else not isAssociativeExp(operand);
      end if;
    end if;

    if parenthesize then
      str := "(" + str + ")";
    end if;
  end operandFlatString;

  function multaryString
    input list<Expression> arguments;
    input Expression exp;
    input Operator operator;
    input Boolean parenthesize = true;
    output String str;
  algorithm
    str := stringDelimitList(list(operandString(e, exp, false) for e in arguments), Operator.symbol(operator));
    if parenthesize and listLength(arguments) > 1 then
      str := "(" + str + ")";
    end if;
  end multaryString;

  function multaryFlatString
    input list<Expression> arguments;
    input Expression exp;
    input Operator operator;
    input Boolean parenthesize = true;
    output String str;
  algorithm
    str := stringDelimitList(list(operandFlatString(e, exp, false) for e in arguments), Operator.symbol(operator));
    if parenthesize and listLength(arguments) > 1 then
      str := "(" + str + ")";
    end if;
  end multaryFlatString;

  function priority
    input Expression exp;
    input Boolean lhs;
    output Integer priority;
  algorithm
    priority := match exp
      case INTEGER() then if exp.value < 0 then 4 else 0;
      case REAL() then if exp.value < 0.0 then 4 else 0;
      case MULTARY() then Operator.priority(exp.operator, lhs);
      case BINARY() then Operator.priority(exp.operator, lhs);
      case UNARY() then 4;
      case LBINARY() then Operator.priority(exp.operator, lhs);
      case LUNARY() then 7;
      case RELATION() then 6;
      case RANGE() then 10;
      case IF() then 11;
      case CAST() then priority(exp.exp, lhs);
      case BOX() then priority(exp.exp, lhs);
      case UNBOX() then priority(exp.exp, lhs);
      else 0;
    end match;
  end priority;

  function isAssociativeExp
    input Expression exp;
    output Boolean isAssociative;
  algorithm
    isAssociative := match exp
      case BINARY() then Operator.isAssociative(exp.operator);
      case LBINARY() then true;
      else false;
    end match;
  end isAssociativeExp;

  function isNonAssociativeExp
    input Expression exp;
    output Boolean isAssociative;
  algorithm
    isAssociative := match exp
      case BINARY() then Operator.isNonAssociative(exp.operator);
      case LBINARY() then true;
      else false;
    end match;
  end isNonAssociativeExp;

  function getName
    "Returns the 'name' of an Expression, for example the function name of a
     call or the record class name of a record expression."
    input Expression exp;
    output String name;
  algorithm
    name := match exp
      case RECORD() then AbsynUtil.pathString(exp.path);
      case CALL() then AbsynUtil.pathString(Call.functionName(exp.call));
      case CAST() then getName(exp.exp);
      case BOX() then getName(exp.exp);
      case UNBOX() then getName(exp.exp);
      case MUTABLE() then getName(Mutable.access(exp.exp));
      case PARTIAL_FUNCTION_APPLICATION() then ComponentRef.toString(exp.fn);
      else toString(exp);
    end match;
  end getName;

  function enumLiteralPath
    input Expression exp;
    output Absyn.Path path;
  protected
    String name;
    Absyn.Path ty_path;
  algorithm
    ENUM_LITERAL(name = name, ty = Type.ENUMERATION(typePath = ty_path)) := exp;
    path := AbsynUtil.suffixPath(ty_path, name);
  end enumLiteralPath;

  function toAbsynOpt
    input Option<Expression> exp;
    output Option<Absyn.Exp> aexp;
  algorithm
    aexp := match exp
      local
        Expression e;

      case SOME(e) then SOME(toAbsyn(e));
      else NONE();
    end match;
  end toAbsynOpt;

  function toAbsyn
    input Expression exp;
    output Absyn.Exp aexp;
  algorithm
    aexp := match exp
      local
        Type ty;

      case INTEGER() then Absyn.Exp.INTEGER(exp.value);
      case REAL() then Absyn.Exp.REAL(String(exp.value));
      case STRING() then Absyn.Exp.STRING(exp.value);
      case BOOLEAN() then Absyn.Exp.BOOL(exp.value);
      case ENUM_LITERAL(ty = ty as Type.ENUMERATION())
        then Absyn.Exp.CREF(AbsynUtil.pathToCref(enumLiteralPath(exp)));
      case CLKCONST() then ClockKind.toAbsyn(exp.clk);
      case CREF() then Absyn.Exp.CREF(ComponentRef.toAbsyn(exp.cref));
      case TYPENAME() then Absyn.Exp.CREF(Absyn.ComponentRef.CREF_IDENT(Type.toString(exp.ty), {}));
      case ARRAY() then Absyn.Exp.ARRAY(list(toAbsyn(e) for e in exp.elements));
      case MATRIX() then Absyn.Exp.MATRIX(list(list(toAbsyn(e) for e in l) for l in exp.elements));
      case RANGE() then Absyn.Exp.RANGE(toAbsyn(exp.start), toAbsynOpt(exp.step), toAbsyn(exp.stop));
      case TUPLE() then Absyn.Exp.TUPLE(list(toAbsyn(e) for e in exp.elements));
      case RECORD() then AbsynUtil.makeCall(AbsynUtil.pathToCref(exp.path), list(toAbsyn(e) for e in exp.elements));
      case CALL() then Call.toAbsyn(exp.call);
      case SIZE() then AbsynUtil.makeCall(Absyn.ComponentRef.CREF_IDENT("size", {}),
        if isSome(exp.dimIndex) then {toAbsyn(Util.getOption(exp.dimIndex))} else {});
      case END() then Absyn.Exp.END();
      case BINARY() then Absyn.Exp.BINARY(toAbsyn(exp.exp1), Operator.toAbsyn(exp.operator), toAbsyn(exp.exp2));
      case UNARY() then Absyn.Exp.UNARY(Operator.toAbsyn(exp.operator), toAbsyn(exp.exp));
      case LBINARY() then Absyn.Exp.LBINARY(toAbsyn(exp.exp1), Operator.toAbsyn(exp.operator), toAbsyn(exp.exp2));
      case LUNARY() then Absyn.Exp.LUNARY(Operator.toAbsyn(exp.operator), toAbsyn(exp.exp));
      case RELATION() then Absyn.Exp.RELATION(toAbsyn(exp.exp1), Operator.toAbsyn(exp.operator), toAbsyn(exp.exp2));
      case IF() then Absyn.Exp.IFEXP(toAbsyn(exp.condition), toAbsyn(exp.trueBranch), toAbsyn(exp.falseBranch), {});
      case CAST() then toAbsyn(exp.exp);
      case BOX() then toAbsyn(exp.exp);
      case UNBOX() then toAbsyn(exp.exp);
      case MUTABLE() then toAbsyn(Mutable.access(exp.exp));
      case PARTIAL_FUNCTION_APPLICATION()
        then Absyn.Exp.PARTEVALFUNCTION(ComponentRef.toAbsyn(exp.fn),
          Absyn.FunctionArgs.FUNCTIONARGS(list(toAbsyn(e) for e in exp.args), {}));
      case FILENAME() then Absyn.Exp.STRING(exp.filename);

      else
        algorithm
          Error.assertion(false, getInstanceName() + " got unknown expression '" + toString(exp) + "'", sourceInfo());
        then
          fail();

    end match;
  end toAbsyn;

  function toDAEOpt
    input Option<Expression> exp;
    output Option<DAE.Exp> dexp;
  algorithm
    dexp := match exp
      local
        Expression e;

      case SOME(e) then SOME(toDAE(e));
      else NONE();
    end match;
  end toDAEOpt;

  function toDAE
    input Expression exp;
    output DAE.Exp dexp;
  protected
    Boolean changed = true;
  algorithm
    dexp := match exp
      local
        DAE.Operator daeOp;
        Boolean swap, negate;
        DAE.Exp dae1, dae2;
        Function.Function fn;

      case INTEGER() then DAE.ICONST(exp.value);
      case REAL() then DAE.RCONST(exp.value);
      case STRING() then DAE.SCONST(exp.value);
      case BOOLEAN() then DAE.BCONST(exp.value);
      case ENUM_LITERAL() then DAE.ENUM_LITERAL(enumLiteralPath(exp), exp.index);

      case CLKCONST()
        then DAE.CLKCONST(ClockKind.toDAE(exp.clk));

      case CREF()
        then DAE.CREF(ComponentRef.toDAE(exp.cref), Type.toDAE(exp.ty));

      case TYPENAME()
        then toDAE(ExpandExp.expandTypename(exp.ty));

      case ARRAY()
        then DAE.ARRAY(Type.toDAE(exp.ty), Type.isVector(exp.ty),
          list(toDAE(e) for e in exp.elements));

      case RECORD() then toDAERecord(exp.ty, exp.path, exp.elements);

      case RANGE()
        then DAE.RANGE(
               Type.toDAE(exp.ty),
               toDAE(exp.start),
               if isSome(exp.step)
               then SOME(toDAE(Util.getOption(exp.step)))
               else NONE(),
               toDAE(exp.stop));

      case TUPLE() then DAE.TUPLE(list(toDAE(e) for e in exp.elements));
      case CALL() then Call.toDAE(exp.call);

      case SIZE()
        then DAE.SIZE(toDAE(exp.exp),
               if isSome(exp.dimIndex)
               then SOME(toDAE(Util.getOption(exp.dimIndex)))
               else NONE());

      // END() doesn't have a DAE representation.

      case MULTARY() algorithm
        // swapping not necessary because multary expressions have to be commutative
      then toDAEMultary(exp.arguments, exp.inv_arguments, exp.operator);

      case BINARY()
        algorithm
          (daeOp, swap, negate) := Operator.toDAE(exp.operator);
          dae1 := toDAE(exp.exp1);
          dae2 := toDAE(if negate then negate(exp.exp2) else exp.exp2);
        then
          DAE.BINARY(if swap then dae2 else dae1, daeOp, if swap then dae1 else dae2);

      case UNARY() then DAE.UNARY(Operator.toDAE(exp.operator), toDAE(exp.exp));
      case LBINARY() then DAE.LBINARY(toDAE(exp.exp1), Operator.toDAE(exp.operator), toDAE(exp.exp2));
      case LUNARY() then DAE.LUNARY(Operator.toDAE(exp.operator), toDAE(exp.exp));
      case RELATION() then DAE.RELATION(toDAE(exp.exp1), Operator.toDAE(exp.operator), toDAE(exp.exp2), -1, NONE());
      case IF() then DAE.IFEXP(toDAE(exp.condition), toDAE(exp.trueBranch), toDAE(exp.falseBranch));
      case CAST() then DAE.CAST(Type.toDAE(exp.ty), toDAE(exp.exp));
      case BOX() then DAE.BOX(toDAE(exp.exp));
      case UNBOX() then DAE.UNBOX(toDAE(exp.exp), Type.toDAE(exp.ty));

      case SUBSCRIPTED_EXP()
        then DAE.ASUB(toDAE(exp.exp), list(Subscript.toDAEExp(s) for s in exp.subscripts));

      case TUPLE_ELEMENT()
        then DAE.TSUB(toDAE(exp.tupleExp), exp.index, Type.toDAE(exp.ty));

      case RECORD_ELEMENT()
        then DAE.RSUB(toDAE(exp.recordExp), exp.index, exp.fieldName, Type.toDAE(exp.ty));

      case PARTIAL_FUNCTION_APPLICATION()
        algorithm
          fn :: _ := Function.Function.typeRefCache(exp.fn);
        then
          DAE.PARTEVALFUNCTION(Function.Function.nameConsiderBuiltin(fn),
                               list(toDAE(arg) for arg in exp.args),
                               Type.toDAE(exp.ty),
                               Type.toDAE(Type.FUNCTION(fn, NFType.FunctionType.FUNCTIONAL_VARIABLE)));

      case MUTABLE() then toDAE(Mutable.access(exp.exp));
      case FILENAME()
        then if Flags.getConfigBool(Flags.BUILDING_FMU) then
               DAE.CALL(Absyn.Path.IDENT("OpenModelica_fmuLoadResource"),
                        {DAE.SCONST(exp.filename)}, DAE.callAttrBuiltinImpureString)
             else
               DAE.SCONST(exp.filename);

      else
        algorithm
          Error.assertion(false, getInstanceName() + " got unknown expression '" + toString(exp) + "'", sourceInfo());
        then
          fail();

    end match;
  end toDAE;

  function toDAEMultary
    "Converts a multary expression to a chain of binary expressions because
    the old frontend does not have multary expressions."
    input list<Expression> arguments;
    input list<Expression> inv_arguments;
    input Operator operator;
    output DAE.Exp daeExp;
  algorithm
    if listEmpty(inv_arguments) then
      daeExp := toDAEMultaryArgs(arguments, operator);
    elseif Type.isBoolean(operator.ty) then
      daeExp := DAE.LBINARY(
        exp1      = toDAEMultaryArgs(arguments, operator),
        operator  = Operator.toDAE(Operator.invert(operator)),
        exp2      = toDAEMultaryArgs(inv_arguments, operator)
       );
    else
      daeExp := DAE.BINARY(
        exp1      = toDAEMultaryArgs(arguments, operator),
        operator  = Operator.toDAE(Operator.invert(operator)),
        exp2      = toDAEMultaryArgs(inv_arguments, operator)
       );
     end if;
  end toDAEMultary;

  function toDAEMultaryArgs
    input list<Expression> arguments;
    input Operator operator;
    output DAE.Exp daeExp;
  protected
    DAE.Operator daeOp;
  algorithm
    daeExp := match arguments
      local
        Expression arg;
        list<Expression> rest;
        DAE.Exp exp;

      // list is empty from the get-go: create neutral element
      case {} guard(Operator.getMathClassification(operator) == NFOperator.MathClassification.ADDITION)
      then toDAE(makeZero(operator.ty));
      case {} guard(Operator.getMathClassification(operator) == NFOperator.MathClassification.MULTIPLICATION)
      then toDAE(makeOne(operator.ty));

      // no rest, just return the DAE representation of last argument
      case arg :: {} then toDAE(arg);

      // convert argument to DAE and create new binary. recurse for second argument
      case arg :: rest algorithm
        exp := toDAE(arg);
       (daeOp, _) := Operator.toDAE(operator);
      then  DAE.BINARY(exp, daeOp, toDAEMultary(rest, {}, operator));

      else algorithm
        Error.assertion(false, getInstanceName() + " got unhandled argument list:
        {" + stringDelimitList(list(toString(e) for e in arguments), ", ") + "}", sourceInfo());
      then fail();
    end match;
  end toDAEMultaryArgs;

  function toDAERecord
    input Type ty;
    input Absyn.Path path;
    input list<Expression> args;
    output DAE.Exp exp;
  protected
    list<String> field_names = {};
    Expression arg;
    list<Expression> rest_args = args;
    list<DAE.Exp> dargs = {};
  algorithm
    for field in Type.recordFields(Type.unbox(ty)) loop
      arg :: rest_args := rest_args;

      () := match field
        case Record.Field.INPUT()
          algorithm
            field_names := field.name :: field_names;
            dargs := toDAE(arg) :: dargs;
          then
            ();

        // TODO: Constants/parameters shouldn't be added to record expressions
        //       since that causes issues with the backend, but removing them
        //       currently causes even worse issues.
        case Record.Field.LOCAL()
          algorithm
            field_names := field.name :: field_names;
            dargs := toDAE(arg) :: dargs;
          then
            ();

        else ();
      end match;
    end for;

    field_names := listReverseInPlace(field_names);
    dargs := listReverseInPlace(dargs);

    exp := if Type.isBoxed(ty) then
        DAE.METARECORDCALL(path, dargs, field_names, -1, {})
      else
        DAE.RECORD(path, dargs, field_names, Type.toDAE(ty));
  end toDAERecord;

  function toDAEValueOpt
    input Option<Expression> exp;
    output Option<Values.Value> value = Util.applyOption(exp, toDAEValue);
  end toDAEValueOpt;

  function toDAEValue
    input Expression exp;
    output Values.Value value;
  algorithm
    value := match exp
      local
        Type ty;

      case INTEGER() then Values.INTEGER(exp.value);
      case REAL() then Values.REAL(exp.value);
      case STRING() then Values.STRING(exp.value);
      case BOOLEAN() then Values.BOOL(exp.value);
      case ENUM_LITERAL(ty = ty as Type.ENUMERATION())
        then Values.ENUM_LITERAL(AbsynUtil.suffixPath(ty.typePath, exp.name), exp.index);
      case ARRAY() then ValuesUtil.makeArray(list(toDAEValue(e) for e in exp.elements));
      case RECORD() then toDAEValueRecord(exp.ty, exp.path, exp.elements);
      case FILENAME() then Values.STRING(exp.filename);

      else
        algorithm
          Error.assertion(false, getInstanceName() + " got unhandled expression " + toString(exp), sourceInfo());
        then
          fail();
    end match;
  end toDAEValue;

  function toDAEValueRecord
    input Type ty;
    input Absyn.Path path;
    input list<Expression> args;
    output Values.Value value;
  protected
    list<String> field_names = {};
    Expression arg;
    list<Expression> rest_args = args;
    list<Values.Value> values = {};
  algorithm
    for field in Type.recordFields(ty) loop
      arg :: rest_args := rest_args;

      () := match field
        case Record.Field.INPUT()
          algorithm
            field_names := field.name :: field_names;
            values := toDAEValue(arg) :: values;
          then
            ();

        else ();
      end match;
    end for;

    field_names := listReverseInPlace(field_names);
    values := listReverseInPlace(values);
    value := Values.RECORD(path, values, field_names, -1);
  end toDAEValueRecord;

  function dimensionCount
    input Expression exp;
    output Integer dimCount;
  algorithm
    dimCount := match exp
      case ARRAY(ty = Type.UNKNOWN())
        then 1 + dimensionCount(arrayGet(exp.elements, 1));
      case ARRAY() then Type.dimensionCount(exp.ty);
      case RANGE() then Type.dimensionCount(exp.ty);
      case SIZE(dimIndex = NONE()) then dimensionCount(exp.exp);
      case CAST() then dimensionCount(exp.exp);
      case SUBSCRIPTED_EXP() then Type.dimensionCount(exp.ty);
      case TUPLE_ELEMENT() then Type.dimensionCount(exp.ty);
      // TODO: Add more expressions.
      else 0;
    end match;
  end dimensionCount;

  function dimensions
    input Expression exp;
    output list<Dimension> dims;
  algorithm
    dims := Type.arrayDims(typeOf(exp));
  end dimensions;

  function map
    "Applies a function recursively (depth-first, post-order) to an expression
     and creates a new expression from the returned values.
     NOTE: For performance reasons this function does not recurse into arrays
           marked as literal."
    input Expression exp;
    input MapFunc func;
    output Expression outExp;

    partial function MapFunc
      input output Expression e;
    end MapFunc;
  algorithm
    outExp := match exp
      local
        Expression e1, e2, e3, e4;

      case CLKCONST() then CLKCONST(ClockKind.mapExp(exp.clk, func));
      case CREF() then CREF(exp.ty, ComponentRef.mapExp(exp.cref, func));
      case ARRAY() guard not exp.literal then makeArray(exp.ty, Array.map(exp.elements, function map(func = func)), exp.literal);
      case MATRIX() then MATRIX(list(list(map(e, func) for e in row) for row in exp.elements));

      case RANGE(step = SOME(e2))
        algorithm
          e1 := map(exp.start, func);
          e4 := map(e2, func);
          e3 := map(exp.stop, func);
        then
          if referenceEq(exp.start, e1) and referenceEq(e2, e4) and
            referenceEq(exp.stop, e3) then exp else RANGE(exp.ty, e1, SOME(e4), e3);

      case RANGE()
        algorithm
          e1 := map(exp.start, func);
          e3 := map(exp.stop, func);
        then
          if referenceEq(exp.start, e1) and referenceEq(exp.stop, e3)
            then exp else RANGE(exp.ty, e1, NONE(), e3);

      case TUPLE() then TUPLE(exp.ty, list(map(e, func) for e in exp.elements));

      case RECORD()
        then RECORD(exp.path, exp.ty, list(map(e, func) for e in exp.elements));

      case CALL() then CALL(Call.mapExp(exp.call, func));

      case SIZE(dimIndex = SOME(e2))
        algorithm
          e1 := map(exp.exp, func);
          e3 := map(e2, func);
        then
          if referenceEq(exp.exp, e1) and referenceEq(e2, e3) then exp else SIZE(e1, SOME(e3));

      case SIZE()
        algorithm
          e1 := map(exp.exp, func);
        then
          if referenceEq(exp.exp, e1) then exp else SIZE(e1, NONE());

      case BINARY()
        algorithm
          e1 := map(exp.exp1, func);
          e2 := map(exp.exp2, func);
        then
          if referenceEq(exp.exp1, e1) and referenceEq(exp.exp2, e2)
            then exp else BINARY(e1, exp.operator, e2);

      case MULTARY()
        algorithm
          // ToDo: referenceEq ?
          exp.arguments := list(map(arg, func) for arg in exp.arguments);
          exp.inv_arguments := list(map(arg, func) for arg in exp.inv_arguments);
        then exp;

      case UNARY()
        algorithm
          e1 := map(exp.exp, func);
        then
          if referenceEq(exp.exp, e1) then exp else UNARY(exp.operator, e1);

      case LBINARY()
        algorithm
          e1 := map(exp.exp1, func);
          e2 := map(exp.exp2, func);
        then
          if referenceEq(exp.exp1, e1) and referenceEq(exp.exp2, e2)
            then exp else LBINARY(e1, exp.operator, e2);

      case LUNARY()
        algorithm
          e1 := map(exp.exp, func);
        then
          if referenceEq(exp.exp, e1) then exp else LUNARY(exp.operator, e1);

      case RELATION()
        algorithm
          e1 := map(exp.exp1, func);
          e2 := map(exp.exp2, func);
        then
          if referenceEq(exp.exp1, e1) and referenceEq(exp.exp2, e2)
            then exp else RELATION(e1, exp.operator, e2);

      case IF()
        algorithm
          e1 := map(exp.condition, func);
          e2 := map(exp.trueBranch, func);
          e3 := map(exp.falseBranch, func);
        then
          if referenceEq(exp.condition, e1) and referenceEq(exp.trueBranch, e2) and
             referenceEq(exp.falseBranch, e3) then exp else IF(exp.ty, e1, e2, e3);

      case CAST()
        algorithm
          e1 := map(exp.exp, func);
        then
          if referenceEq(exp.exp, e1) then exp else CAST(exp.ty, e1);

      case BOX()
        algorithm
          e1 := map(exp.exp, func);
        then
          if referenceEq(exp.exp, e1) then exp else box(e1);

      case UNBOX()
        algorithm
          e1 := map(exp.exp, func);
        then
          if referenceEq(exp.exp, e1) then exp else unbox(e1);

      case SUBSCRIPTED_EXP()
        then SUBSCRIPTED_EXP(map(exp.exp, func),
          list(Subscript.mapExp(s, func) for s in exp.subscripts), exp.ty, exp.split);

      case TUPLE_ELEMENT()
        algorithm
          e1 := map(exp.tupleExp, func);
        then
          if referenceEq(exp.tupleExp, e1) then exp else TUPLE_ELEMENT(e1, exp.index, exp.ty);

      case RECORD_ELEMENT()
        algorithm
          e1 := map(exp.recordExp, func);
        then
          if referenceEq(exp.recordExp, e1) then exp else RECORD_ELEMENT(e1, exp.index, exp.fieldName, exp.ty);

      case MUTABLE()
        algorithm
          Mutable.update(exp.exp, map(Mutable.access(exp.exp), func));
        then
          exp;

      case PARTIAL_FUNCTION_APPLICATION()
        algorithm
          exp.args := list(map(e, func) for e in exp.args);
        then
          exp;

      else exp;
    end match;

    outExp := func(outExp);
  end map;

  function mapOpt
    input Option<Expression> exp;
    input MapFunc func;
    output Option<Expression> outExp;

    partial function MapFunc
      input output Expression e;
    end MapFunc;
  protected
    Expression e;
  algorithm
    outExp := match exp
      case SOME(e) then SOME(map(e, func));
      else exp;
    end match;
  end mapOpt;

  function mapReverse
    "Applies a function recursively (depth-first, pre-order) to an expression
     and creates a new expression from the returned values.
     NOTE: For performance reasons this function does not recurse into arrays
           marked as literal."
    input output Expression exp;
    input MapFunc func;

    partial function MapFunc
      input output Expression e;
    end MapFunc;
  algorithm
    exp := func(exp);
    exp := match exp
      local
        Expression e1, e2, e3, e4;

      case CLKCONST() then CLKCONST(ClockKind.mapExp(exp.clk, func));
      case CREF() then CREF(exp.ty, ComponentRef.mapExp(exp.cref, func));
      case ARRAY() guard not exp.literal then makeArray(exp.ty, Array.map(exp.elements, function mapReverse(func = func)), exp.literal);
      case MATRIX() then MATRIX(list(list(mapReverse(e, func) for e in row) for row in exp.elements));

      case RANGE(step = SOME(e2))
        algorithm
          e1 := mapReverse(exp.start, func);
          e4 := mapReverse(e2, func);
          e3 := mapReverse(exp.stop, func);
        then
          if referenceEq(exp.start, e1) and referenceEq(e2, e4) and
            referenceEq(exp.stop, e3) then exp else RANGE(exp.ty, e1, SOME(e4), e3);

      case RANGE()
        algorithm
          e1 := mapReverse(exp.start, func);
          e3 := mapReverse(exp.stop, func);
        then
          if referenceEq(exp.start, e1) and referenceEq(exp.stop, e3)
            then exp else RANGE(exp.ty, e1, NONE(), e3);

      case TUPLE() then TUPLE(exp.ty, list(mapReverse(e, func) for e in exp.elements));

      case RECORD()
        then RECORD(exp.path, exp.ty, list(mapReverse(e, func) for e in exp.elements));

      case CALL() then CALL(Call.mapExp(exp.call, func));

      case SIZE(dimIndex = SOME(e2))
        algorithm
          e1 := mapReverse(exp.exp, func);
          e3 := mapReverse(e2, func);
        then
          if referenceEq(exp.exp, e1) and referenceEq(e2, e3) then exp else SIZE(e1, SOME(e3));

      case SIZE()
        algorithm
          e1 := mapReverse(exp.exp, func);
        then
          if referenceEq(exp.exp, e1) then exp else SIZE(e1, NONE());

      case BINARY()
        algorithm
          e1 := mapReverse(exp.exp1, func);
          e2 := mapReverse(exp.exp2, func);
        then
          if referenceEq(exp.exp1, e1) and referenceEq(exp.exp2, e2)
            then exp else BINARY(e1, exp.operator, e2);

      case MULTARY()
        algorithm
          // ToDo: referenceEq ?
          exp.arguments := list(mapReverse(arg, func) for arg in exp.arguments);
          exp.inv_arguments := list(mapReverse(arg, func) for arg in exp.inv_arguments);
        then exp;

      case UNARY()
        algorithm
          e1 := mapReverse(exp.exp, func);
        then
          if referenceEq(exp.exp, e1) then exp else UNARY(exp.operator, e1);

      case LBINARY()
        algorithm
          e1 := mapReverse(exp.exp1, func);
          e2 := mapReverse(exp.exp2, func);
        then
          if referenceEq(exp.exp1, e1) and referenceEq(exp.exp2, e2)
            then exp else LBINARY(e1, exp.operator, e2);

      case LUNARY()
        algorithm
          e1 := mapReverse(exp.exp, func);
        then
          if referenceEq(exp.exp, e1) then exp else LUNARY(exp.operator, e1);

      case RELATION()
        algorithm
          e1 := mapReverse(exp.exp1, func);
          e2 := mapReverse(exp.exp2, func);
        then
          if referenceEq(exp.exp1, e1) and referenceEq(exp.exp2, e2)
            then exp else RELATION(e1, exp.operator, e2);

      case IF()
        algorithm
          e1 := mapReverse(exp.condition, func);
          e2 := mapReverse(exp.trueBranch, func);
          e3 := mapReverse(exp.falseBranch, func);
        then
          if referenceEq(exp.condition, e1) and referenceEq(exp.trueBranch, e2) and
             referenceEq(exp.falseBranch, e3) then exp else IF(exp.ty, e1, e2, e3);

      case CAST()
        algorithm
          e1 := mapReverse(exp.exp, func);
        then
          if referenceEq(exp.exp, e1) then exp else CAST(exp.ty, e1);

      case BOX()
        algorithm
          e1 := mapReverse(exp.exp, func);
        then
          if referenceEq(exp.exp, e1) then exp else box(e1);

      case UNBOX()
        algorithm
          e1 := mapReverse(exp.exp, func);
        then
          if referenceEq(exp.exp, e1) then exp else unbox(e1);

      case SUBSCRIPTED_EXP()
        then SUBSCRIPTED_EXP(mapReverse(exp.exp, func),
          list(Subscript.mapExp(s, func) for s in exp.subscripts), exp.ty, exp.split);

      case TUPLE_ELEMENT()
        algorithm
          e1 := mapReverse(exp.tupleExp, func);
        then
          if referenceEq(exp.tupleExp, e1) then exp else TUPLE_ELEMENT(e1, exp.index, exp.ty);

      case RECORD_ELEMENT()
        algorithm
          e1 := mapReverse(exp.recordExp, func);
        then
          if referenceEq(exp.recordExp, e1) then exp else RECORD_ELEMENT(e1, exp.index, exp.fieldName, exp.ty);

      case MUTABLE()
        algorithm
          Mutable.update(exp.exp, mapReverse(Mutable.access(exp.exp), func));
        then
          exp;

      case PARTIAL_FUNCTION_APPLICATION()
        algorithm
          exp.args := list(mapReverse(e, func) for e in exp.args);
        then
          exp;

      else exp;
    end match;
  end mapReverse;

  function mapShallow
    "Applies a function recursively to each subexpression in an expression,
     without recursion, and creates a new expression from the returned values.
     NOTE: For performance reasons this function does not recurse into arrays
           marked as literal."
    input Expression exp;
    input MapFunc func;
    output Expression outExp;

    partial function MapFunc
      input output Expression e;
    end MapFunc;
  algorithm
    outExp := match exp
      local
        Expression e1, e2, e3, e4;

      case CLKCONST() then CLKCONST(ClockKind.mapExpShallow(exp.clk, func));
      case CREF() then CREF(exp.ty, ComponentRef.mapExpShallow(exp.cref, func));
      case ARRAY() guard not exp.literal then makeArray(exp.ty, Array.map(exp.elements, func), exp.literal);
      case MATRIX() then MATRIX(list(list(func(e) for e in row) for row in exp.elements));

      case RANGE(step = SOME(e2))
        algorithm
          e1 := func(exp.start);
          e4 := func(e2);
          e3 := func(exp.stop);
        then
          if referenceEq(exp.start, e1) and referenceEq(e2, e4) and
            referenceEq(exp.stop, e3) then exp else RANGE(exp.ty, e1, SOME(e4), e3);

      case RANGE()
        algorithm
          e1 := func(exp.start);
          e3 := func(exp.stop);
        then
          if referenceEq(exp.start, e1) and referenceEq(exp.stop, e3)
            then exp else RANGE(exp.ty, e1, NONE(), e3);

      case TUPLE() then TUPLE(exp.ty, list(func(e) for e in exp.elements));

      case RECORD()
        then RECORD(exp.path, exp.ty, list(func(e) for e in exp.elements));

      case CALL() then CALL(Call.mapExpShallow(exp.call, func));

      case SIZE(dimIndex = SOME(e2))
        algorithm
          e1 := func(exp.exp);
          e3 := func(e2);
        then
          if referenceEq(exp.exp, e1) and referenceEq(e2, e3) then exp else SIZE(e1, SOME(e3));

      case SIZE()
        algorithm
          e1 := func(exp.exp);
        then
          if referenceEq(exp.exp, e1) then exp else SIZE(e1, NONE());

      case BINARY()
        algorithm
          e1 := func(exp.exp1);
          e2 := func(exp.exp2);
        then
          if referenceEq(exp.exp1, e1) and referenceEq(exp.exp2, e2)
            then exp else BINARY(e1, exp.operator, e2);

      case MULTARY()
        algorithm
          // ToDo: referenceEq ?
          exp.arguments := list(func(arg) for arg in exp.arguments);
          exp.inv_arguments := list(func(arg) for arg in exp.inv_arguments);
        then exp;

      case UNARY()
        algorithm
          e1 := func(exp.exp);
        then
          if referenceEq(exp.exp, e1) then exp else UNARY(exp.operator, e1);

      case LBINARY()
        algorithm
          e1 := func(exp.exp1);
          e2 := func(exp.exp2);
        then
          if referenceEq(exp.exp1, e1) and referenceEq(exp.exp2, e2)
            then exp else LBINARY(e1, exp.operator, e2);

      case LUNARY()
        algorithm
          e1 := func(exp.exp);
        then
          if referenceEq(exp.exp, e1) then exp else LUNARY(exp.operator, e1);

      case RELATION()
        algorithm
          e1 := func(exp.exp1);
          e2 := func(exp.exp2);
        then
          if referenceEq(exp.exp1, e1) and referenceEq(exp.exp2, e2)
            then exp else RELATION(e1, exp.operator, e2);

      case IF()
        algorithm
          e1 := func(exp.condition);
          e2 := func(exp.trueBranch);
          e3 := func(exp.falseBranch);
        then
          if referenceEq(exp.condition, e1) and referenceEq(exp.trueBranch, e2) and
             referenceEq(exp.falseBranch, e3) then exp else IF(exp.ty, e1, e2, e3);

      case CAST()
        algorithm
          e1 := func(exp.exp);
        then
          if referenceEq(exp.exp, e1) then exp else CAST(exp.ty, e1);

      case BOX()
        algorithm
          e1 := func(exp.exp);
        then
          if referenceEq(exp.exp, e1) then exp else box(e1);

      case UNBOX()
        algorithm
          e1 := func(exp.exp);
        then
          if referenceEq(exp.exp, e1) then exp else unbox(e1);

      case SUBSCRIPTED_EXP()
        then SUBSCRIPTED_EXP(func(exp.exp),
          list(Subscript.mapShallowExp(e, func) for e in exp.subscripts), exp.ty, exp.split);

      case TUPLE_ELEMENT()
        algorithm
          e1 := func(exp.tupleExp);
        then
          if referenceEq(exp.tupleExp, e1) then exp else TUPLE_ELEMENT(e1, exp.index, exp.ty);

      case RECORD_ELEMENT()
        algorithm
          e1 := func(exp.recordExp);
        then
          if referenceEq(exp.recordExp, e1) then exp else RECORD_ELEMENT(e1, exp.index, exp.fieldName, exp.ty);

      case MUTABLE()
        algorithm
          Mutable.update(exp.exp, func(Mutable.access(exp.exp)));
        then
          exp;

      case PARTIAL_FUNCTION_APPLICATION()
        algorithm
          exp.args := list(func(e) for e in exp.args);
        then
          exp;

      else exp;
    end match;
  end mapShallow;

  function mapShallowOpt
    input Option<Expression> exp;
    input MapFunc func;
    output Option<Expression> outExp;

    partial function MapFunc
      input output Expression e;
    end MapFunc;
  protected
    Expression e;
  algorithm
    outExp := match exp
      case SOME(e) then SOME(func(e));
      else exp;
    end match;
  end mapShallowOpt;

  function mapArrayElements
    "Applies the given function to each scalar elements of an array."
    input Expression exp;
    input MapFunc func;
    output Expression outExp;

    partial function MapFunc
      input output Expression e;
    end MapFunc;
  algorithm
    outExp := match exp
      case ARRAY()
        algorithm
          exp.elements := Array.map(exp.elements, function mapArrayElements(func = func));
          exp.literal := Array.all(exp.elements, isLiteral);
        then
          exp;

      else func(exp);
    end match;
  end mapArrayElements;

  function foldArray<ArgT>
    input array<Expression> expl;
    input FoldFunc func;
    input ArgT arg;
    output ArgT result = arg;

    partial function FoldFunc
      input Expression exp;
      input output ArgT arg;
    end FoldFunc;
  algorithm
    for e in expl loop
      result := fold(e, func, result);
    end for;
  end foldArray;

  function foldList<ArgT>
    input list<Expression> expl;
    input FoldFunc func;
    input ArgT arg;
    output ArgT result = arg;

    partial function FoldFunc
      input Expression exp;
      input output ArgT arg;
    end FoldFunc;
  algorithm
    for e in expl loop
      result := fold(e, func, result);
    end for;
  end foldList;

  function foldOpt<ArgT>
    input Option<Expression> exp;
    input FoldFunc func;
    input ArgT arg;
    output ArgT result;

    partial function FoldFunc
      input Expression exp;
      input output ArgT arg;
    end FoldFunc;
  algorithm
    result := match exp
      local
        Expression e;

      case SOME(e) then func(e, arg);
      else arg;
    end match;
  end foldOpt;

  function fold<ArgT>
    input Expression exp;
    input FoldFunc func;
    input ArgT arg;
    output ArgT result;

    partial function FoldFunc
      input Expression exp;
      input output ArgT arg;
    end FoldFunc;
  algorithm
    result := match exp
      local
        Expression e, e1, e2;

      case CLKCONST() then ClockKind.foldExp(exp.clk, func, arg);
      case CREF() then ComponentRef.foldExp(exp.cref, func, arg);
      case ARRAY() then foldArray(exp.elements, func, arg);

      case MATRIX()
        algorithm
          result := arg;
          for row in exp.elements loop
            result := foldList(row, func, result);
          end for;
        then
          result;

      case RANGE()
        algorithm
          result := fold(exp.start, func, arg);
          result := foldOpt(exp.step, func, result);
        then
          fold(exp.stop, func, result);

      case TUPLE() then foldList(exp.elements, func, arg);
      case RECORD() then foldList(exp.elements, func, arg);
      case CALL() then Call.foldExp(exp.call, func, arg);

      case SIZE(dimIndex = SOME(e))
        algorithm
          result := fold(exp.exp, func, arg);
        then
          fold(e, func, result);

      case SIZE() then fold(exp.exp, func, arg);

      case BINARY()
        algorithm
          result := fold(exp.exp1, func, arg);
        then
          fold(exp.exp2, func, result);

      case MULTARY()
        algorithm
          result := arg;
          for argument in exp.arguments loop
            result := fold(argument, func, result);
          end for;
          for argument in exp.inv_arguments loop
            result := fold(argument, func, result);
          end for;
        then
          result;

      case UNARY() then fold(exp.exp, func, arg);

      case LBINARY()
        algorithm
          result := fold(exp.exp1, func, arg);
        then
          fold(exp.exp2, func, result);

      case LUNARY() then fold(exp.exp, func, arg);

      case RELATION()
        algorithm
          result := fold(exp.exp1, func, arg);
        then
          fold(exp.exp2, func, result);

      case IF()
        algorithm
          result := fold(exp.condition, func, arg);
          result := fold(exp.trueBranch, func, result);
        then
          fold(exp.falseBranch, func, result);

      case CAST() then fold(exp.exp, func, arg);
      case BOX() then fold(exp.exp, func, arg);
      case UNBOX() then fold(exp.exp, func, arg);

      case SUBSCRIPTED_EXP()
        algorithm
          result := fold(exp.exp, func, arg);
        then
          List.fold(exp.subscripts, function Subscript.foldExp(func = func), result);

      case TUPLE_ELEMENT() then fold(exp.tupleExp, func, arg);
      case RECORD_ELEMENT() then fold(exp.recordExp, func, arg);
      case MUTABLE() then fold(Mutable.access(exp.exp), func, arg);
      case PARTIAL_FUNCTION_APPLICATION() then foldList(exp.args, func, arg);
      else arg;
    end match;

    result := func(exp, result);
  end fold;

  function applyArray
    input array<Expression> expl;
    input ApplyFunc func;

    partial function ApplyFunc
      input Expression exp;
    end ApplyFunc;
  algorithm
    for e in expl loop
      apply(e, func);
    end for;
  end applyArray;

  function applyList
    input list<Expression> expl;
    input ApplyFunc func;

    partial function ApplyFunc
      input Expression exp;
    end ApplyFunc;
  algorithm
    for e in expl loop
      apply(e, func);
    end for;
  end applyList;

  function applyOpt
    input Option<Expression> exp;
    input ApplyFunc func;

    partial function ApplyFunc
      input Expression exp;
    end ApplyFunc;
  protected
    Expression e;
  algorithm
    if isSome(exp) then
      SOME(e) := exp;
      apply(e, func);
    end if;
  end applyOpt;

  function apply
    input Expression exp;
    input ApplyFunc func;

    partial function ApplyFunc
      input Expression exp;
    end ApplyFunc;
  algorithm
    () := match exp
      local
        Expression e, e1, e2;

      case CLKCONST() algorithm ClockKind.applyExp(exp.clk, func); then ();
      case CREF() algorithm ComponentRef.applyExp(exp.cref, func); then ();
      case ARRAY() algorithm applyArray(exp.elements, func); then ();

      case MATRIX()
        algorithm
          for row in exp.elements loop
            applyList(row, func);
          end for;
        then
          ();

      case RANGE()
        algorithm
          apply(exp.start, func);
          applyOpt(exp.step, func);
          apply(exp.stop, func);
        then
          ();

      case TUPLE() algorithm applyList(exp.elements, func); then ();
      case RECORD() algorithm applyList(exp.elements, func); then ();
      case CALL() algorithm Call.applyExp(exp.call, func); then ();

      case SIZE()
        algorithm
          apply(exp.exp, func);
          applyOpt(exp.dimIndex, func);
        then
          ();

      case BINARY()
        algorithm
          apply(exp.exp1, func);
          apply(exp.exp2, func);
        then
          ();

      case MULTARY()
        algorithm
          for arg in exp.arguments loop
            apply(arg, func);
          end for;
          for arg in exp.inv_arguments loop
            apply(arg, func);
          end for;
        then ();

      case UNARY() algorithm apply(exp.exp, func); then ();

      case LBINARY()
        algorithm
          apply(exp.exp1, func);
          apply(exp.exp2, func);
        then
          ();

      case LUNARY() algorithm apply(exp.exp, func); then ();

      case RELATION()
        algorithm
          apply(exp.exp1, func);
          apply(exp.exp2, func);
        then
          ();

      case IF()
        algorithm
          apply(exp.condition, func);
          apply(exp.trueBranch, func);
          apply(exp.falseBranch, func);
        then
          ();

      case CAST() algorithm apply(exp.exp, func); then ();
      case BOX() algorithm apply(exp.exp, func); then ();
      case UNBOX() algorithm apply(exp.exp, func); then ();

      case SUBSCRIPTED_EXP()
        algorithm
          apply(exp.exp, func);

          for s in exp.subscripts loop
            Subscript.applyExp(s, func);
          end for;
        then
          ();

      case TUPLE_ELEMENT() algorithm apply(exp.tupleExp, func); then ();
      case RECORD_ELEMENT() algorithm apply(exp.recordExp, func); then ();
      case MUTABLE() algorithm apply(Mutable.access(exp.exp), func); then ();
      case PARTIAL_FUNCTION_APPLICATION() algorithm applyList(exp.args, func); then ();
      else ();
    end match;

    func(exp);
  end apply;

  function applyArrayShallow
    input array<Expression> expl;
    input ApplyFunc func;

    partial function ApplyFunc
      input Expression exp;
    end ApplyFunc;
  algorithm
    for e in expl loop
      func(e);
    end for;
  end applyArrayShallow;

  function applyListShallow
    input list<Expression> expl;
    input ApplyFunc func;

    partial function ApplyFunc
      input Expression exp;
    end ApplyFunc;
  algorithm
    for e in expl loop
      func(e);
    end for;
  end applyListShallow;

  function applyShallow
    input Expression exp;
    input ApplyFunc func;

    partial function ApplyFunc
      input Expression exp;
    end ApplyFunc;
  algorithm
    () := match exp
      local
        Expression e;

      case CLKCONST() algorithm ClockKind.applyExpShallow(exp.clk, func); then ();
      case CREF() algorithm ComponentRef.applyExpShallow(exp.cref, func); then ();
      case ARRAY() algorithm applyArrayShallow(exp.elements, func); then ();

      case MATRIX()
        algorithm
          for row in exp.elements loop
            applyList(row, func);
          end for;
        then
          ();

      case RANGE()
        algorithm
          func(exp.start);
          applyShallowOpt(exp.step, func);
          func(exp.stop);
        then
          ();

      case TUPLE() algorithm applyListShallow(exp.elements, func); then ();
      case RECORD() algorithm applyListShallow(exp.elements, func); then ();
      case CALL() algorithm Call.applyExpShallow(exp.call, func); then ();

      case SIZE()
        algorithm
          func(exp.exp);
          applyShallowOpt(exp.dimIndex, func);
        then
          ();

      case BINARY()
        algorithm
          func(exp.exp1);
          func(exp.exp2);
        then
          ();

      case MULTARY()
        algorithm
          for arg in exp.arguments loop
            func(arg);
          end for;
          for arg in exp.inv_arguments loop
            func(arg);
          end for;
        then ();

      case UNARY() algorithm func(exp.exp); then ();

      case LBINARY()
        algorithm
          func(exp.exp1);
          func(exp.exp2);
        then
          ();

      case LUNARY() algorithm func(exp.exp); then ();

      case RELATION()
        algorithm
          func(exp.exp1);
          func(exp.exp2);
        then
          ();

      case IF()
        algorithm
          func(exp.condition);
          func(exp.trueBranch);
          func(exp.falseBranch);
        then
          ();

      case CAST() algorithm func(exp.exp); then ();
      case BOX() algorithm func(exp.exp); then ();
      case UNBOX() algorithm func(exp.exp); then ();

      case SUBSCRIPTED_EXP()
        algorithm
          func(exp.exp);

          for s in exp.subscripts loop
            Subscript.applyExpShallow(s, func);
          end for;
        then
          ();

      case TUPLE_ELEMENT() algorithm func(exp.tupleExp); then ();
      case RECORD_ELEMENT() algorithm func(exp.recordExp); then ();
      case MUTABLE() algorithm func(Mutable.access(exp.exp)); then ();
      case PARTIAL_FUNCTION_APPLICATION() algorithm applyListShallow(exp.args, func); then ();
      else ();
    end match;
  end applyShallow;

  function applyShallowOpt
    input Option<Expression> exp;
    input ApplyFunc func;

    partial function ApplyFunc
      input Expression exp;
    end ApplyFunc;
  protected
    Expression e;
  algorithm
    if isSome(exp) then
      SOME(e) := exp;
      func(e);
    end if;
  end applyShallowOpt;

  function mapFold<ArgT>
    input Expression exp;
    input MapFunc func;
    output Expression outExp;
    input output ArgT arg;

    partial function MapFunc
      input output Expression e;
      input output ArgT arg;
    end MapFunc;
  algorithm
    outExp := match exp
      local
        Expression e1, e2, e3, e4;
        ComponentRef cr;
        list<Expression> expl;
        Call call;
        list<Subscript> subs;
        ClockKind ck;
        list<list<Expression>> mat;
        array<Expression> arr;

      case CLKCONST()
        algorithm
          (ck, arg) := ClockKind.mapFoldExp(exp.clk, func, arg);
        then
          if referenceEq(exp.clk, ck) then exp else CLKCONST(ck);

      case CREF()
        algorithm
          (cr, arg) := ComponentRef.mapFoldExp(exp.cref, func, arg);
       then
          if referenceEq(exp.cref, cr) then exp else CREF(exp.ty, cr);

      case ARRAY()
        algorithm
          (arr, arg) := Array.mapFold(exp.elements, function mapFold(func = func), arg);
        then
          makeArray(exp.ty, arr, exp.literal);

      case MATRIX()
        algorithm
          (mat, arg) := List.mapFoldList(exp.elements, function mapFold(func = func), arg);
        then
          MATRIX(mat);

      case RANGE(step = SOME(e2))
        algorithm
          (e1, arg) := mapFold(exp.start, func, arg);
          (e4, arg) := mapFold(e2, func, arg);
          (e3, arg) := mapFold(exp.stop, func, arg);
        then
          if referenceEq(exp.start, e1) and referenceEq(e2, e4) and
            referenceEq(exp.stop, e3) then exp else RANGE(exp.ty, e1, SOME(e4), e3);

      case RANGE()
        algorithm
          (e1, arg) := mapFold(exp.start, func, arg);
          (e3, arg) := mapFold(exp.stop, func, arg);
        then
          if referenceEq(exp.start, e1) and referenceEq(exp.stop, e3)
            then exp else RANGE(exp.ty, e1, NONE(), e3);

      case TUPLE()
        algorithm
          (expl, arg) := List.map1Fold(exp.elements, mapFold, func, arg);
        then
          TUPLE(exp.ty, expl);

      case RECORD()
        algorithm
          (expl, arg) := List.map1Fold(exp.elements, mapFold, func, arg);
        then
          RECORD(exp.path, exp.ty, expl);

      case CALL()
        algorithm
          (call, arg) := Call.mapFoldExp(exp.call, func, arg);
        then
          if referenceEq(exp.call, call) then exp else CALL(call);

      case SIZE(dimIndex = SOME(e2))
        algorithm
          (e1, arg) := mapFold(exp.exp, func, arg);
          (e3, arg) := mapFold(e2, func, arg);
        then
          if referenceEq(exp.exp, e1) and referenceEq(e2, e3) then exp else SIZE(e1, SOME(e3));

      case SIZE()
        algorithm
          (e1, arg) := mapFold(exp.exp, func, arg);
        then
          if referenceEq(exp.exp, e1) then exp else SIZE(e1, NONE());

      case BINARY()
        algorithm
          (e1, arg) := mapFold(exp.exp1, func, arg);
          (e2, arg) := mapFold(exp.exp2, func, arg);
        then
          if referenceEq(exp.exp1, e1) and referenceEq(exp.exp2, e2)
            then exp else BINARY(e1, exp.operator, e2);

      case MULTARY()
        algorithm
          // ToDo: referenceEq ?
          expl := {};
          for argument in exp.arguments loop
            (e1, arg) := mapFold(argument, func, arg);
            expl := e1 :: expl;
          end for;
          exp.arguments := listReverse(expl);
          expl := {};
          for argument in exp.inv_arguments loop
            (e1, arg) := mapFold(argument, func, arg);
            expl := e1 :: expl;
          end for;
          exp.inv_arguments := listReverse(expl);
        then exp;

      case UNARY()
        algorithm
          (e1, arg) := mapFold(exp.exp, func, arg);
        then
          if referenceEq(exp.exp, e1) then exp else UNARY(exp.operator, e1);

      case LBINARY()
        algorithm
          (e1, arg) := mapFold(exp.exp1, func, arg);
          (e2, arg) := mapFold(exp.exp2, func, arg);
        then
          if referenceEq(exp.exp1, e1) and referenceEq(exp.exp2, e2)
            then exp else LBINARY(e1, exp.operator, e2);

      case LUNARY()
        algorithm
          (e1, arg) := mapFold(exp.exp, func, arg);
        then
          if referenceEq(exp.exp, e1) then exp else LUNARY(exp.operator, e1);

      case RELATION()
        algorithm
          (e1, arg) := mapFold(exp.exp1, func, arg);
          (e2, arg) := mapFold(exp.exp2, func, arg);
        then
          if referenceEq(exp.exp1, e1) and referenceEq(exp.exp2, e2)
            then exp else RELATION(e1, exp.operator, e2);

      case IF()
        algorithm
          (e1, arg) := mapFold(exp.condition, func, arg);
          (e2, arg) := mapFold(exp.trueBranch, func, arg);
          (e3, arg) := mapFold(exp.falseBranch, func, arg);
        then
          if referenceEq(exp.condition, e1) and referenceEq(exp.trueBranch, e2) and
             referenceEq(exp.falseBranch, e3) then exp else IF(exp.ty, e1, e2, e3);

      case CAST()
        algorithm
          (e1, arg) := mapFold(exp.exp, func, arg);
        then
          if referenceEq(exp.exp, e1) then exp else CAST(exp.ty, e1);

      case BOX()
        algorithm
          (e1, arg) := mapFold(exp.exp, func, arg);
        then
          if referenceEq(exp.exp, e1) then exp else box(e1);

      case UNBOX()
        algorithm
          (e1, arg) := mapFold(exp.exp, func, arg);
        then
          if referenceEq(exp.exp, e1) then exp else unbox(e1);

      case SUBSCRIPTED_EXP()
        algorithm
          (e1, arg) := mapFold(exp.exp, func, arg);
          (subs, arg) := List.mapFold(exp.subscripts, function Subscript.mapFoldExp(func = func), arg);
        then
          SUBSCRIPTED_EXP(e1, subs, exp.ty, exp.split);

      case TUPLE_ELEMENT()
        algorithm
          (e1, arg) := mapFold(exp.tupleExp, func, arg);
        then
          if referenceEq(exp.tupleExp, e1) then exp else TUPLE_ELEMENT(e1, exp.index, exp.ty);

      case RECORD_ELEMENT()
        algorithm
          (e1, arg) := mapFold(exp.recordExp, func, arg);
        then
          if referenceEq(exp.recordExp, e1) then exp else RECORD_ELEMENT(e1, exp.index, exp.fieldName, exp.ty);

      case MUTABLE()
        algorithm
          (e1, arg) := mapFold(Mutable.access(exp.exp), func, arg);
          Mutable.update(exp.exp, e1);
        then
          exp;

      case PARTIAL_FUNCTION_APPLICATION()
        algorithm
          (expl, arg) := List.map1Fold(exp.args, mapFold, func, arg);
          exp.args := expl;
        then
          exp;

      else exp;
    end match;

    (outExp, arg) := func(outExp, arg);
  end mapFold;

  function mapFoldOpt<ArgT>
    input Option<Expression> exp;
    input MapFunc func;
          output Option<Expression> outExp;
    input output ArgT arg;

    partial function MapFunc
      input output Expression e;
      input output ArgT arg;
    end MapFunc;
  protected
    Expression e;
  algorithm
    outExp := match exp
      case SOME(e)
        algorithm
          (e, arg) := mapFold(e, func, arg);
        then
          SOME(e);

      else exp;
    end match;
  end mapFoldOpt;

  function mapFoldShallow<ArgT>
    input Expression exp;
    input MapFunc func;
          output Expression outExp;
    input output ArgT arg;

    partial function MapFunc
      input output Expression e;
      input output ArgT arg;
    end MapFunc;
  algorithm
    outExp := match exp
      local
        Expression e1, e2, e3, e4;
        Option<Expression> oe;
        ComponentRef cr;
        list<Expression> expl;
        Call call;
        list<Subscript> subs;
        Boolean unchanged;
        ClockKind ck;
        list<list<Expression>> mat;
        array<Expression> arr;

      case CLKCONST()
        algorithm
          (ck, arg) := ClockKind.mapFoldExpShallow(exp.clk, func, arg);
        then
          if referenceEq(exp.clk, ck) then exp else CLKCONST(ck);

      case CREF()
        algorithm
          (cr, arg) := ComponentRef.mapFoldExpShallow(exp.cref, func, arg);
       then
          if referenceEq(exp.cref, cr) then exp else CREF(exp.ty, cr);

      case ARRAY()
        algorithm
          (arr, arg) := Array.mapFold(exp.elements, func, arg);
        then
          makeArray(exp.ty, arr, exp.literal);

      case MATRIX()
        algorithm
          (mat, arg) := List.mapFoldList(exp.elements, func, arg);
        then
          MATRIX(mat);

      case RANGE(step = oe)
        algorithm
          (e1, arg) := func(exp.start, arg);
          (oe, arg) := mapFoldOptShallow(exp.step, func, arg);
          (e3, arg) := func(exp.stop, arg);
        then
          if referenceEq(e1, exp.start) and referenceEq(oe, exp.step) and referenceEq(e3, exp.stop) then
            exp else RANGE(exp.ty, e1, oe, e3);

      case TUPLE()
        algorithm
          (expl, arg) := List.mapFold(exp.elements, func, arg);
        then
          TUPLE(exp.ty, expl);

      case RECORD()
        algorithm
          (expl, arg) := List.mapFold(exp.elements, func, arg);
        then
          RECORD(exp.path, exp.ty, expl);

      case CALL()
        algorithm
          (call, arg) := Call.mapFoldExpShallow(exp.call, func, arg);
        then
          if referenceEq(exp.call, call) then exp else CALL(call);

      case SIZE()
        algorithm
          (e1, arg) := func(exp.exp, arg);
          (oe, arg) := mapFoldOptShallow(exp.dimIndex, func, arg);
        then
          if referenceEq(exp.exp, e1) and referenceEq(exp.dimIndex, oe) then
            exp else SIZE(e1, oe);

      case BINARY()
        algorithm
          (e1, arg) := func(exp.exp1, arg);
          (e2, arg) := func(exp.exp2, arg);
        then
          if referenceEq(exp.exp1, e1) and referenceEq(exp.exp2, e2)
            then exp else BINARY(e1, exp.operator, e2);

      case MULTARY()
        algorithm
          // ToDo: referenceEq ?
          expl := {};
          for argument in exp.arguments loop
            (e1, arg) := func(argument, arg);
            expl := e1 :: expl;
          end for;
          exp.arguments := listReverse(expl);
          expl := {};
          for argument in exp.inv_arguments loop
            (e1, arg) := func(argument, arg);
            expl := e1 :: expl;
          end for;
          exp.inv_arguments := listReverse(expl);
        then exp;

      case UNARY()
        algorithm
          (e1, arg) := func(exp.exp, arg);
        then
          if referenceEq(exp.exp, e1) then exp else UNARY(exp.operator, e1);

      case LBINARY()
        algorithm
          (e1, arg) := func(exp.exp1, arg);
          (e2, arg) := func(exp.exp2, arg);
        then
          if referenceEq(exp.exp1, e1) and referenceEq(exp.exp2, e2)
            then exp else LBINARY(e1, exp.operator, e2);

      case LUNARY()
        algorithm
          (e1, arg) := func(exp.exp, arg);
        then
          if referenceEq(exp.exp, e1) then exp else LUNARY(exp.operator, e1);

      case RELATION()
        algorithm
          (e1, arg) := func(exp.exp1, arg);
          (e2, arg) := func(exp.exp2, arg);
        then
          if referenceEq(exp.exp1, e1) and referenceEq(exp.exp2, e2)
            then exp else RELATION(e1, exp.operator, e2);

      case IF()
        algorithm
          (e1, arg) := func(exp.condition, arg);
          (e2, arg) := func(exp.trueBranch, arg);
          (e3, arg) := func(exp.falseBranch, arg);
        then
          if referenceEq(exp.condition, e1) and referenceEq(exp.trueBranch, e2) and
             referenceEq(exp.falseBranch, e3) then exp else IF(exp.ty, e1, e2, e3);

      case CAST()
        algorithm
          (e1, arg) := func(exp.exp, arg);
        then
          if referenceEq(exp.exp, e1) then exp else CAST(exp.ty, e1);

      case BOX()
        algorithm
          (e1, arg) := func(exp.exp, arg);
        then
          if referenceEq(exp.exp, e1) then exp else box(e1);

      case UNBOX()
        algorithm
          (e1, arg) := func(exp.exp, arg);
        then
          if referenceEq(exp.exp, e1) then exp else unbox(e1);

      case SUBSCRIPTED_EXP()
        algorithm
          (e1, arg) := func(exp.exp, arg);
          (subs, arg) := List.mapFold(exp.subscripts, function Subscript.mapFoldExpShallow(func = func), arg);
        then
          SUBSCRIPTED_EXP(e1, subs, exp.ty, exp.split);

      case TUPLE_ELEMENT()
        algorithm
          (e1, arg) := func(exp.tupleExp, arg);
        then
          if referenceEq(exp.tupleExp, e1) then exp else TUPLE_ELEMENT(e1, exp.index, exp.ty);

      case RECORD_ELEMENT()
        algorithm
          (e1, arg) := func(exp.recordExp, arg);
        then
          if referenceEq(exp.recordExp, e1) then exp else RECORD_ELEMENT(e1, exp.index, exp.fieldName, exp.ty);

      case MUTABLE()
        algorithm
          (e1, arg) := func(Mutable.access(exp.exp), arg);
          Mutable.update(exp.exp, e1);
        then
          exp;

      case PARTIAL_FUNCTION_APPLICATION()
        algorithm
          (expl, arg) := List.mapFold(exp.args, func, arg);
          exp.args := expl;
        then
          exp;

      else exp;
    end match;
  end mapFoldShallow;

  function mapFoldOptShallow<ArgT>
    input Option<Expression> exp;
    input MapFunc func;
          output Option<Expression> outExp;
    input output ArgT arg;

    partial function MapFunc
      input output Expression e;
      input output ArgT arg;
    end MapFunc;
  protected
    Expression e1, e2;
  algorithm
    outExp := match exp
      case SOME(e1)
        algorithm
          (e2, arg) := func(e1, arg);
        then
          if referenceEq(e1, e2) then exp else SOME(e2);

      else exp;
    end match;
  end mapFoldOptShallow;

  function containsOpt
    input Option<Expression> exp;
    input ContainsPred func;
    output Boolean res;

    partial function ContainsPred
      input Expression exp;
      output Boolean res;
    end ContainsPred;
  protected
    Expression e;
  algorithm
    res := match exp
      case SOME(e) then contains(e, func);
      else false;
    end match;
  end containsOpt;

  function contains
    input Expression exp;
    input ContainsPred func;
    output Boolean res;

    partial function ContainsPred
      input Expression exp;
      output Boolean res;
    end ContainsPred;
  algorithm
    if func(exp) then
      res := true;
      return;
    end if;

    res := match exp
      local
        Expression e;

      case CLKCONST() then ClockKind.containsExp(exp.clk, func);
      case CREF() then ComponentRef.containsExp(exp.cref, func);
      case ARRAY() then arrayContains(exp.elements, func);

      case MATRIX()
        algorithm
          res := false;

          for row in exp.elements loop
            if listContains(row, func) then
              res := true;
              break;
            end if;
          end for;
        then
          res;

      case RANGE()
        then contains(exp.start, func) or
             containsOpt(exp.step, func) or
             contains(exp.stop, func);

      case TUPLE() then listContains(exp.elements, func);
      case RECORD() then listContains(exp.elements, func);
      case CALL() then Call.containsExp(exp.call, func);

      case SIZE()
        then containsOpt(exp.dimIndex, func) or
             contains(exp.exp, func);

      case BINARY() then contains(exp.exp1, func) or contains(exp.exp2, func);
      case MULTARY()
        algorithm
          res := false;
          for arg in exp.arguments loop
            if res then break; end if;
            res := contains(arg, func);
          end for;
          for arg in exp.inv_arguments loop
            if res then break; end if;
            res := contains(arg, func);
          end for;
        then res;
      case UNARY() then contains(exp.exp, func);
      case LBINARY() then contains(exp.exp1, func) or contains(exp.exp2, func);
      case LUNARY() then contains(exp.exp, func);
      case RELATION() then contains(exp.exp1, func) or contains(exp.exp2, func);

      case IF()
        then contains(exp.condition, func) or
             contains(exp.trueBranch, func) or
             contains(exp.falseBranch, func);

      case CAST() then contains(exp.exp, func);
      case BOX() then contains(exp.exp, func);
      case UNBOX() then contains(exp.exp, func);

      case SUBSCRIPTED_EXP()
        then contains(exp.exp, func) or Subscript.listContainsExp(exp.subscripts, func);

      case TUPLE_ELEMENT() then contains(exp.tupleExp, func);
      case RECORD_ELEMENT() then contains(exp.recordExp, func);
      case MUTABLE() then contains(Mutable.access(exp.exp), func);
      case PARTIAL_FUNCTION_APPLICATION() then listContains(exp.args, func);
      else false;
    end match;
  end contains;

  function arrayContains
    input array<Expression> expl;
    input ContainsPred func;
    output Boolean res;

    partial function ContainsPred
      input Expression exp;
      output Boolean res;
    end ContainsPred;
  algorithm
    for e in expl loop
      if contains(e, func) then
        res := true;
        return;
      end if;
    end for;

    res := false;
  end arrayContains;

  function listContains
    input list<Expression> expl;
    input ContainsPred func;
    output Boolean res;

    partial function ContainsPred
      input Expression exp;
      output Boolean res;
    end ContainsPred;
  algorithm
    for e in expl loop
      if contains(e, func) then
        res := true;
        return;
      end if;
    end for;

    res := false;
  end listContains;

  function containsShallow
    input Expression exp;
    input ContainsPred func;
    output Boolean res;

    partial function ContainsPred
      input Expression exp;
      output Boolean res;
    end ContainsPred;
  algorithm
    res := match exp
      case CLKCONST() then ClockKind.containsExpShallow(exp.clk, func);
      case CREF() then ComponentRef.containsExpShallow(exp.cref, func);
      case ARRAY() then Array.exist(exp.elements, func);

      case MATRIX()
        algorithm
          res := false;

          for row in exp.elements loop
            if List.exist(row, func) then
              res := true;
              break;
            end if;
          end for;
        then
          res;

      case RANGE()
        then func(exp.start) or
             Util.applyOptionOrDefault(exp.step, func, false) or
             func(exp.stop);

      case TUPLE() then List.exist(exp.elements, func);
      case RECORD() then List.exist(exp.elements, func);
      case CALL() then Call.containsExpShallow(exp.call, func);

      case SIZE()
        then Util.applyOptionOrDefault(exp.dimIndex, func, false) or
             func(exp.exp);

      case BINARY() then func(exp.exp1) or func(exp.exp2);
      case MULTARY()
        algorithm
          res := false;
          for arg in exp.arguments loop
            if res then break; end if;
            res := func(arg);
          end for;
          for arg in exp.inv_arguments loop
            if res then break; end if;
            res := func(arg);
          end for;
        then res;
      case UNARY() then func(exp.exp);
      case LBINARY() then func(exp.exp1) or func(exp.exp2);
      case LUNARY() then func(exp.exp);
      case RELATION() then func(exp.exp1) or func(exp.exp2);
      case IF() then func(exp.condition) or func(exp.trueBranch) or func(exp.falseBranch);
      case CAST() then func(exp.exp);
      case BOX() then func(exp.exp);
      case UNBOX() then func(exp.exp);

      case SUBSCRIPTED_EXP()
        then func(exp.exp) or Subscript.listContainsExpShallow(exp.subscripts, func);

      case TUPLE_ELEMENT() then func(exp.tupleExp);
      case RECORD_ELEMENT() then func(exp.recordExp);
      case MUTABLE() then func(Mutable.access(exp.exp));
      case PARTIAL_FUNCTION_APPLICATION() then listContains(exp.args, func);
      else false;
    end match;
  end containsShallow;

  function arrayFirstScalar
    "Returns the first scalar element of an array. Fails if the array is empty."
    input Expression arrayExp;
    output Expression exp;
  algorithm
    exp := match arrayExp
      case ARRAY() then arrayFirstScalar(arrayGet(arrayExp.elements, 1));
      else arrayExp;
    end match;
  end arrayFirstScalar;

  function arrayAllEqual
    "Checks if all scalar elements in an array are equal to each other."
    input Expression arrayExp;
    output Boolean allEqual;
  algorithm
    allEqual := matchcontinue arrayExp
      case ARRAY() then arrayAllEqual2(arrayExp, arrayFirstScalar(arrayExp));
      else true;
    end matchcontinue;
  end arrayAllEqual;

  function arrayAllEqual2
    input Expression arrayExp;
    input Expression element;
    output Boolean allEqual;
  algorithm
    allEqual := match arrayExp
      case ARRAY()
        guard not arrayEmpty(arrayExp.elements) and isArray(arrayGet(arrayExp.elements, 1))
        then Array.mapBoolAnd(arrayExp.elements, function arrayAllEqual2(element = element));
      case ARRAY()
        then Array.mapBoolAnd(arrayExp.elements, function isEqual(exp2 = element));
      else true;
    end match;
  end arrayAllEqual2;

  function fromCref
    input ComponentRef cref;
    input Boolean includeScope = false;
    output Expression exp;
  algorithm
    exp := CREF(ComponentRef.getSubscriptedType(cref, includeScope), cref);
  end fromCref;

  function toCref
    input Expression exp;
    output ComponentRef cref;
  algorithm
    CREF(cref = cref) := exp;
  end toCref;

  function extract
    "author: kabdelhak 2020-06
    Extracts all sub expressions from an expression using a filter function."
    input Expression exp;
    input filter func;
    output list<Expression> exp_lst;
    partial function filter
      input Expression exp;
      output Boolean b;
    end filter;
  protected
    // traverse helper function only needed in this function
    function traverser
      input Expression exp;
      input filter func;
      input output list<Expression> exp_lst;
      partial function filter
        input Expression exp;
        output Boolean b;
      end filter;
    algorithm
      exp_lst := if func(exp) then exp :: exp_lst else exp_lst;
    end traverser;
  algorithm
    exp_lst := fold(exp, function traverser(func = func), {});
  end extract;

  function isIterator
    input Expression exp;
    output Boolean isIterator;
  algorithm
    isIterator := match exp
      case CREF() then ComponentRef.isIterator(exp.cref);
      else false;
    end match;
  end isIterator;

  function containsAnyIterator
    input Expression exp;
    input InstContext.Type context;
    output Boolean iter;
  algorithm
    if InstContext.inFor(context) then
      iter := contains(exp, isIterator);
    else
      iter := false;
    end if;
  end containsAnyIterator;

  function isTime
    input Expression exp;
    output Boolean b;
  algorithm
    b := match exp
      case CREF() then ComponentRef.isTime(exp.cref);
      else false;
    end match;
  end isTime;

  function isZero
    input Expression exp;
    output Boolean isZero;
  algorithm
    isZero := match exp
      case INTEGER() then exp.value == 0;
      case REAL() then exp.value == 0.0;
      case CAST() then isZero(exp.exp);
      case UNARY() then isZero(exp.exp);
      else false;
    end match;
  end isZero;

  function isOne
    input Expression exp;
    output Boolean isOne;
  algorithm
    isOne := match exp
      case INTEGER() then exp.value == 1;
      case REAL() then exp.value == 1.0;
      case CAST() then isOne(exp.exp);
      case UNARY() then isMinusOne(exp.exp);
      else false;
    end match;
  end isOne;

  function isMinusOne
    input Expression exp;
    output Boolean isOne;
  algorithm
    isOne := match exp
      case INTEGER() then exp.value == -1;
      case REAL() then exp.value == -1.0;
      case CAST() then isMinusOne(exp.exp);
      case UNARY() then isOne(exp.exp);
      else false;
    end match;
  end isMinusOne;

  function isNegative
    "this requires proper simplification to be correct"
    input Expression exp;
    output Boolean negative;
  algorithm
    negative := match exp
      case INTEGER() then exp.value < 0;
      case REAL() then exp.value < 0;
      case CAST() then isNegative(exp.exp);
      case UNARY() then not isNegative(exp.exp);
      else false;
    end match;
  end isNegative;

  function isNonPositive
    "Returns true if the expression is a number <= 0, otherwise false."
    input Expression exp;
    output Boolean res;
  algorithm
    res := match exp
      case INTEGER() then exp.value <= 0;
      case REAL() then exp.value <= 0;
      case CAST() then isNonPositive(exp.exp);
      case UNARY() then isNonNegative(exp.exp);
      else false;
    end match;
  end isNonPositive;

  function isNonNegative
    "Returns true if the expression is a number >= 0, otherwise false."
    input Expression exp;
    output Boolean res;
  algorithm
    res := match exp
      case INTEGER() then exp.value >= 0;
      case REAL() then exp.value >= 0;
      case CAST() then isNonNegative(exp.exp);
      case UNARY() then isNonPositive(exp.exp);
      else false;
    end match;
  end isNonNegative;

  function isScalar
    input Expression exp;
    output Boolean scalar = Type.isScalar(typeOf(exp));
  end isScalar;

  function isScalarLiteral
    input Expression exp;
    output Boolean literal;
  algorithm
    literal := match exp
      case INTEGER() then true;
      case REAL() then true;
      case STRING() then true;
      case BOOLEAN() then true;
      case ENUM_LITERAL() then true;
      case FILENAME() then true;
      else false;
    end match;
  end isScalarLiteral;

  function isLiteral
    input Expression exp;
    output Boolean literal;
  algorithm
    literal := match exp
      case INTEGER() then true;
      case REAL() then true;
      case STRING() then true;
      case BOOLEAN() then true;
      case ENUM_LITERAL() then true;
      case ARRAY() then exp.literal or Array.all(exp.elements, isLiteral);
      case RECORD() then List.all(exp.elements, isLiteral);
      case RANGE() then isLiteral(exp.start) and
                        isLiteral(exp.stop) and
                        Util.applyOptionOrDefault(exp.step, isLiteral, true);
      case FILENAME() then true;
      else false;
    end match;
  end isLiteral;

  function isLiteralFill
    input Expression exp;
    output Boolean literal;
  algorithm
    literal := match exp
      case CALL() then Call.isNamed(exp.call, "fill") and List.all(Call.arguments(exp.call), isLiteral);
      else false;
    end match;
  end isLiteralFill;

  function isInteger
    input Expression exp;
    output Boolean isInteger;
  algorithm
    isInteger := match exp
      case INTEGER() then true;
      else false;
    end match;
  end isInteger;

  function isReal
    input Expression exp;
    output Boolean isReal;
  algorithm
    isReal := match exp
      case REAL() then true;
      else false;
    end match;
  end isReal;

  function isConstNumber
    input Expression exp;
    output Boolean b;
  algorithm
    b := match exp
      case INTEGER() then true;
      case REAL() then true;
      case CAST() then isConstNumber(exp.exp);
      case UNARY() then isConstNumber(exp.exp);
      else false;
    end match;
  end isConstNumber;

  function isBoolean
    input Expression exp;
    output Boolean isBool;
  algorithm
    isBool := match exp
      case BOOLEAN() then true;
      else false;
    end match;
  end isBoolean;

  function isRecord
    input Expression exp;
    output Boolean isRecord;
  algorithm
    isRecord := match exp
      case RECORD() then true;
      else false;
    end match;
  end isRecord;

  function isRecordOrRecordArray
    input Expression exp;
    output Boolean isRecord;
  algorithm
    isRecord := match exp
      case RECORD() then true;
      case ARRAY() then Array.all(exp.elements, isRecordOrRecordArray);
      else false;
    end match;
  end isRecordOrRecordArray;

  function fillType
    "Creates an array with the given type, filling it with the given scalar
     expression."
    input Type ty;
    input Expression fillExp;
    output Expression exp = fillExp;
  protected
    list<Dimension> dims = Type.arrayDims(ty);
    Type arr_ty = Type.arrayElementType(ty);
    Boolean is_literal = isLiteral(exp);
  algorithm
    for dim in listReverse(dims) loop
      (exp, arr_ty) := fillArray_impl(Dimension.size(dim), exp, arr_ty, is_literal);
    end for;
  end fillType;

  function fillArgs
    "Creates an array from the given fill expression and list of dimensions,
     similar to fill(fillExp, dims...). Fails if not all dimensions can be
     converted to Integer values."
    input Expression fillExp;
    input list<Expression> dims;
    output Expression result = fillExp;
  protected
    Type arr_ty = typeOf(result);
    Boolean is_literal = isLiteral(fillExp);
  algorithm
    for d in listReverse(dims) loop
      (result, arr_ty) := fillArray_impl(toInteger(d), result, arr_ty, is_literal);
    end for;
  end fillArgs;

  function fillArray
    input Integer n;
    input Expression fillExp;
    output Expression result;
  algorithm
    result := fillArray_impl(n, fillExp, typeOf(fillExp), isLiteral(fillExp));
  end fillArray;

  function fillArray_impl
    input Integer n;
    input Expression fillExp;
    input Type ty;
    input Boolean isLiteral;
    output Expression result;
    output Type resultType;
  protected
    array<Expression> arr;
  algorithm
    arr := Array.generate(n, function clone(exp = fillExp));
    resultType := Type.liftArrayLeft(ty, Dimension.fromInteger(n));
    result := makeArray(resultType, arr, isLiteral);
  end fillArray_impl;

  function liftArray
    "Creates an array with the given dimension, where each element is the given
     expression. Example: liftArray([3], 1) => {1, 1, 1}"
    input Dimension dim;
    input output Expression exp;
          output Type arrayType = typeOf(exp);
  algorithm
    (exp, arrayType) := fillArray_impl(Dimension.size(dim), exp, arrayType, isLiteral(exp));
  end liftArray;

  function liftArrayList
    "Creates an array from the given list of dimensions, where each element is
     the given expression. Example:
       liftArrayList([2, 3], 1) => {{1, 1, 1}, {1, 1, 1}}"
    input list<Dimension> dims;
    input output Expression exp;
          output Type arrayType = typeOf(exp);
  protected
    Boolean is_literal = isLiteral(exp);
  algorithm
    for dim in listReverse(dims) loop
      (exp, arrayType) := fillArray_impl(Dimension.size(dim), exp, arrayType, is_literal);
    end for;
  end liftArrayList;

  function makeZero
    input Type ty;
    output Expression zeroExp;
  algorithm
    zeroExp := match ty
      case Type.REAL() then REAL(0.0);
      case Type.INTEGER() then INTEGER(0);
      case Type.BOOLEAN() then BOOLEAN(false);
      case Type.ARRAY() then fillType(ty, makeZero(Type.arrayElementType(ty)));
      case Type.COMPLEX() then makeOperatorRecordZero(ty.cls);
    end match;
  end makeZero;

  function makeOperatorRecordZero
    input InstNode recordNode;
    output Expression zeroExp;
  protected
    InstNode op_node;
    Function.Function fn;
  algorithm
    op_node := Class.lookupElement("'0'", InstNode.getClass(recordNode));
    Function.Function.instFunctionNode(op_node, NFInstContext.NO_CONTEXT, InstNode.info(InstNode.parent(op_node)));
    {fn} := Function.Function.typeNodeCache(op_node);
    zeroExp := CALL(Call.makeTypedCall(fn, {}, Variability.CONSTANT, Purity.PURE));
    zeroExp := Ceval.evalExp(zeroExp);
  end makeOperatorRecordZero;

  function makeOne
    input Type ty;
    output Expression oneExp;
  algorithm
    oneExp := match ty
      case Type.REAL() then REAL(1.0);
      case Type.INTEGER() then INTEGER(1);
      case Type.ARRAY() then fillType(ty, makeOne(Type.arrayElementType(ty)));
    end match;
  end makeOne;

  function makeMinusOne
    input Type ty;
    output Expression oneExp;
  algorithm
    oneExp := match ty
      case Type.REAL() then REAL(-1.0);
      case Type.INTEGER() then INTEGER(-1);
      case Type.ARRAY() then fillType(ty, makeMinusOne(Type.arrayElementType(ty)));
    end match;
  end makeMinusOne;

  function makeMaxValue
    input Type ty;
    output Expression exp;
  algorithm
    exp := match ty
      case Type.REAL() then REAL(System.realMaxLit());
      case Type.INTEGER() then INTEGER(System.intMaxLit());
      case Type.BOOLEAN() then BOOLEAN(true);
      case Type.ENUMERATION() then ENUM_LITERAL(ty, List.last(ty.literals), listLength(ty.literals));
      case Type.ARRAY() then fillType(ty, makeMaxValue(Type.arrayElementType(ty)));
    end match;
  end makeMaxValue;

  function makeMinValue
    input Type ty;
    output Expression exp;
  algorithm
    exp := match ty
      case Type.REAL() then REAL(-System.realMaxLit());
      case Type.INTEGER() then INTEGER(-System.intMaxLit());
      case Type.BOOLEAN() then BOOLEAN(false);
      case Type.ENUMERATION() then ENUM_LITERAL(ty, listHead(ty.literals), 1);
      case Type.ARRAY() then fillType(ty, makeMinValue(Type.arrayElementType(ty)));
    end match;
  end makeMinValue;

  function makeDefaultValue
    input Type ty;
    output Expression exp;
  algorithm
    exp := match ty
      case Type.INTEGER() then INTEGER(0);
      case Type.REAL() then REAL(0);
      case Type.STRING() then STRING("");
      case Type.BOOLEAN() then BOOLEAN(false);
      case Type.ENUMERATION() then ENUM_LITERAL(ty, listHead(ty.literals), 1);
      case Type.ARRAY() then fillType(ty, makeDefaultValue(Type.arrayElementType(ty)));
      case Type.TUPLE() then TUPLE(ty, list(makeDefaultValue(t) for t in ty.types));
    end match;
  end makeDefaultValue;

  function box
    input Expression exp;
    output Expression boxedExp;
  algorithm
    boxedExp := match exp
      case STRING() then exp;
      case RECORD()
        then RECORD(exp.path, Type.box(exp.ty), list(box(e) for e in exp.elements));
      case BOX() then exp;
      case FILENAME() then exp;
      else BOX(exp);
    end match;
  end box;

  function unbox
    input Expression boxedExp;
    output Expression exp;
  algorithm
    exp := match boxedExp
      local
        Type ty;

      case BOX() then boxedExp.exp;

      else
        algorithm
          ty := typeOf(boxedExp);
        then
          if Type.isBoxed(ty) then UNBOX(boxedExp, Type.unbox(ty)) else boxedExp;

    end match;
  end unbox;

  function isNegated
    input Expression exp;
    output Boolean negated;
  algorithm
    negated := match exp
      case INTEGER() then exp.value < 0;
      case REAL() then exp.value < 0;
      case CAST() then isNegated(exp.exp);
      case UNARY() then true;
      else false;
    end match;
  end isNegated;

  function negate
    "Returns '-exp'"
    input output Expression exp;
  algorithm
    exp := match exp
      case INTEGER() then INTEGER(-exp.value);
      case REAL() then REAL(-exp.value);
      case CAST() then CAST(exp.ty, negate(exp.exp));
      case UNARY() then exp.exp;
      else UNARY(Operator.makeUMinus(typeOf(exp)), exp);
    end match;
  end negate;

  function logicNegate
    "Returns 'not exp'"
    input Expression exp;
    output Expression outExp;
  algorithm
    outExp := match exp
      case BOOLEAN() then BOOLEAN(not exp.value);
      case LUNARY() then exp.exp;
      else LUNARY(Operator.makeNot(typeOf(exp)), exp);
    end match;
  end logicNegate;

  function invertRange
    "inverts the direction of a range"
    input output Expression range;
  algorithm
    range := match range
      local
        Expression step;
      case RANGE(step = SOME(step))  then RANGE(range.ty, range.stop, SOME(negate(step)), range.start);
      case RANGE()                   then RANGE(range.ty, range.stop, SOME(INTEGER(-1)), range.start);
      else algorithm
        Error.addMessage(Error.INTERNAL_ERROR,{getInstanceName() + " failed because expression is not a range: \n"
          + toString(range)});
      then fail();
    end match;
  end invertRange;

  function sliceRange
    "slices the range with a given zero-based start and one-based step"
    input output Expression range;
    input tuple<Integer, Integer, Integer> slice  "start step stop";
  algorithm
    range := match (range, slice)
      local
        Integer start, step, stop;
        Integer slice_start, slice_step, slice_stop;

      case (RANGE(), (slice_start, slice_step, slice_stop)) algorithm
        step := if Util.isSome(range.step) then integerValue(Util.getOption(range.step)) else 1;
        start := integerValue(range.start);
        // shift start and stop accordingly, multiply step
        stop  := start + slice_stop * step;
        start := start + slice_start * step;
        step  := slice_step * step;
      then RANGE(range.ty, INTEGER(start), SOME(INTEGER(step)), INTEGER(stop));

      else algorithm
        Error.addMessage(Error.INTERNAL_ERROR,{getInstanceName() + " failed because expression is not a range: \n"
          + toString(range)});
      then fail();
    end match;
  end sliceRange;

  function arrayElements
    input Expression array;
    output array<Expression> elements;
  algorithm
    ARRAY(elements = elements) := array;
  end arrayElements;

  function arrayElementList
    input Expression array;
    output list<Expression> elements;
  algorithm
    elements := match array
      case ARRAY() then arrayList(array.elements);
    end match;
  end arrayElementList;

  function arrayScalarElements
    input Expression exp;
    output list<Expression> elements;
  algorithm
    elements := listReverseInPlace(arrayScalarElements_impl(exp, {}));
  end arrayScalarElements;

  function arrayScalarElements_impl
    input Expression exp;
    input output list<Expression> elements;
  algorithm
    elements := match exp
      case ARRAY()
        algorithm
          for e in exp.elements loop
            elements := arrayScalarElements_impl(e, elements);
          end for;
        then
          elements;

      else exp :: elements;
    end match;
  end arrayScalarElements_impl;

  function arrayScalarElement
    input Expression arrayExp;
    output Expression scalarExp;
  algorithm
    scalarExp := match arrayExp
      case ARRAY()
        guard arrayLength(arrayExp.elements) == 1
        then arrayGet(arrayExp.elements, 1);
    end match;
  end arrayScalarElement;

  function hasArrayCall
    "Returns true if the given expression contains a function call that returns
     an array, otherwise false."
    input Expression exp;
    output Boolean hasArrayCall;
  algorithm
    hasArrayCall := contains(exp, hasArrayCall2);
  end hasArrayCall;

  function hasArrayCall2
    input Expression exp;
    output Boolean hasArrayCall;
  protected
    Call call;
    Type ty;
  algorithm
    hasArrayCall := match exp
      case CALL(call = call)
        algorithm
          ty := Call.typeOf(call);
        then
          Type.isArray(ty) and Call.isVectorizeable(call);

      case TUPLE_ELEMENT(tupleExp = CALL(call = call))
        algorithm
          ty := Type.nthTupleType(Call.typeOf(call), exp.index);
        then
          Type.isArray(ty) and Call.isVectorizeable(call);

      else false;
    end match;
  end hasArrayCall2;

  function transposeArray
    input Expression arrayExp;
    output Expression outExp;
  protected
    Dimension dim1, dim2;
    list<Dimension> rest_dims;
    Type ty, row_ty;
    list<Expression> expl;
    list<list<Expression>> matrix;
    Boolean literal;
    array<Expression> arr;
    array<array<Expression>> matrix_arr;
  algorithm
    outExp := match arrayExp
      case ARRAY(Type.ARRAY(ty, dim1 :: dim2 :: rest_dims), arr, literal)
        algorithm
          if not arrayEmpty(arr) then
            row_ty := Type.ARRAY(ty, dim1 :: rest_dims);
            matrix_arr := Array.map(arr, arrayElements);
            matrix_arr := Array.transpose(matrix_arr);
            arr := Array.map(matrix_arr, function makeArray(ty = row_ty, literal = literal));
          end if;
        then
          makeArray(Type.ARRAY(ty, dim2 :: dim1 :: rest_dims), arr, literal);
    end match;
  end transposeArray;

  function makeIdentityMatrix
    input Integer n;
    input Type elementType;
    output Expression matrix;
  protected
    array<Expression> row, rows;
    Expression zero, one;
    Type row_ty;
  algorithm
    zero := makeZero(elementType);
    one := makeOne(elementType);

    rows := arrayCreateNoInit(n, zero);
    row_ty := Type.ARRAY(elementType, {Dimension.fromInteger(n)});

    for i in 1:n loop
      row := arrayCreateNoInit(n, zero);

      for j in 1:n loop
        arrayUpdateNoBoundsChecking(row, j, if i == j then one else zero);
      end for;

      arrayUpdateNoBoundsChecking(rows, i, makeArray(row_ty, row, true));
    end for;

    matrix := makeExpArray(rows, row_ty, true);
  end makeIdentityMatrix;

  function promote
    input output Expression e;
    input output Type ty;
    input Integer n;
  protected
    list<Dimension> dims;
    Type ety;
    list<Type> tys = {};
    Boolean is_array;
  algorithm
    // Construct the dimensions that needs to be added.
    dims := list(Dimension.fromInteger(1) for i in Type.dimensionCount(ty):n-1);

    if not listEmpty(dims) then
      // Concatenate the existing dimensions and the added ones.
      dims := listAppend(Type.arrayDims(ty), dims);

      // Construct the result type.
      is_array := Type.isArray(ty);
      ety := Type.arrayElementType(ty);
      ty := Type.liftArrayLeftList(ety, dims);

      // Construct the expression types, to avoid having to create a new type
      // for each subexpression that will be created.
      while not listEmpty(dims) loop
        tys := Type.liftArrayLeftList(ety, dims) :: tys;
        dims := listRest(dims);
      end while;

      e := promote2(e, is_array, n, listReverse(tys));
    end if;
  end promote;

  function promote2
    input Expression exp;
    input Boolean isArray;
    input Integer dims;
    input list<Type> types;
    output Expression outExp;
  algorithm
    outExp := match (exp, types)
      local
        Type ty;
        list<Type> rest_ty;
        Expression arr_exp;
        Boolean expanded;

      // No types left, we're done!
      case (_, {}) then exp;

      // An array, promote each element in the array.
      case (ARRAY(), ty :: rest_ty)
        then makeArray(ty, Array.map(exp.elements,
               function promote2(isArray = false, dims = dims, types = rest_ty)));

      // An expression with array type, but which is not an array expression.
      // Such an expression can't be promoted here, so we create a promote call instead.
      case (_, _) guard isArray
        algorithm
          (outExp, expanded) := ExpandExp.expand(exp);

          if expanded then
            outExp := promote2(outExp, true, dims, types);
          else
            outExp := CALL(Call.makeTypedCall(
              NFBuiltinFuncs.PROMOTE, {exp, INTEGER(dims)}, variability(exp), purity(exp), listHead(types)));
          end if;
        then
          outExp;

      // A scalar expression, promote it as many times as the number of types given.
      else
        algorithm
          outExp := exp;
          for ty in listReverse(types) loop
            outExp := makeArray(ty, arrayCreate(1, outExp));
          end for;
        then
          outExp;

    end match;
  end promote2;

  function variability
    input Expression exp;
    output Variability var;
  algorithm
    var := match exp
      case INTEGER() then Variability.CONSTANT;
      case REAL() then Variability.CONSTANT;
      case STRING() then Variability.CONSTANT;
      case BOOLEAN() then Variability.CONSTANT;
      case ENUM_LITERAL() then Variability.CONSTANT;
      case CLKCONST() then Variability.DISCRETE;
      case CREF() then ComponentRef.variability(exp.cref);
      case TYPENAME() then Variability.CONSTANT;
      case ARRAY() then variabilityArray(exp.elements);
      case MATRIX() then List.fold(exp.elements, variabilityList, Variability.CONSTANT);

      case RANGE()
        algorithm
          var := variability(exp.start);
          var := Prefixes.variabilityMax(var, variability(exp.stop));

          if isSome(exp.step) then
            var := Prefixes.variabilityMax(var, variability(Util.getOption(exp.step)));
          end if;
        then
          var;

      case TUPLE() then variabilityList(exp.elements);
      case RECORD() then variabilityList(exp.elements);
      case CALL() then Call.variability(exp.call);
      case SIZE()
        algorithm
          if isSome(exp.dimIndex) then
            var := Prefixes.variabilityMax(Variability.PARAMETER,
                                           variability(Util.getOption(exp.dimIndex)));
          else
            var := Variability.PARAMETER;
          end if;
        then
          var;

      case END() then Variability.PARAMETER;
      case MULTARY() then Prefixes.variabilityMax(variabilityList(exp.arguments), variabilityList(exp.arguments));
      case BINARY() then Prefixes.variabilityMax(variability(exp.exp1), variability(exp.exp2));
      case UNARY() then variability(exp.exp);
      case LBINARY() then Prefixes.variabilityMax(variability(exp.exp1), variability(exp.exp2));
      case LUNARY() then variability(exp.exp);
      case RELATION()
        then Prefixes.variabilityMin(
          Prefixes.variabilityMax(variability(exp.exp1), variability(exp.exp2)),
          Variability.DISCRETE);

      case IF()
        then Prefixes.variabilityMax(variability(exp.condition),
          Prefixes.variabilityMax(variability(exp.trueBranch), variability(exp.falseBranch)));

      case CAST() then variability(exp.exp);
      case BOX() then variability(exp.exp);
      case UNBOX() then variability(exp.exp);
      case SUBSCRIPTED_EXP()
        then Prefixes.variabilityMax(variability(exp.exp), Subscript.variabilityList(exp.subscripts));
      case TUPLE_ELEMENT() then variability(exp.tupleExp);
      case RECORD_ELEMENT() then variability(exp.recordExp);
      case MUTABLE() then variability(Mutable.access(exp.exp));
      case EMPTY() then Variability.CONSTANT;
      case PARTIAL_FUNCTION_APPLICATION() then Variability.CONTINUOUS;
      case FILENAME() then Variability.CONSTANT;
      else
        algorithm
          Error.assertion(false, getInstanceName() + " got unknown expression.", sourceInfo());
        then
          fail();
    end match;
  end variability;

  function variabilityArray
    input array<Expression> expl;
    input output Variability var = Variability.CONSTANT;
  algorithm
    for e in expl loop
      var := Prefixes.variabilityMax(var, variability(e));
    end for;
  end variabilityArray;

  function variabilityList
    input list<Expression> expl;
    input output Variability var = Variability.CONSTANT;
  algorithm
    for e in expl loop
      var := Prefixes.variabilityMax(var, variability(e));
    end for;
  end variabilityList;

  function purity
    input Expression exp;
    output Purity pur;
  algorithm
    pur := match exp
      case INTEGER() then Purity.PURE;
      case REAL() then Purity.PURE;
      case STRING() then Purity.PURE;
      case BOOLEAN() then Purity.PURE;
      case ENUM_LITERAL() then Purity.PURE;
      case CLKCONST() then Purity.PURE;
      case CREF() then ComponentRef.purity(exp.cref);
      case TYPENAME() then Purity.PURE;
      case ARRAY() then purityArray(exp.elements);
      case MATRIX() then List.fold(exp.elements, purityList, Purity.PURE);

      case RANGE()
        algorithm
          pur := purity(exp.start);
          pur := Prefixes.purityMin(pur, purity(exp.stop));

          if isSome(exp.step) then
            pur := Prefixes.purityMin(pur, purity(Util.getOption(exp.step)));
          end if;
        then
          pur;

      case TUPLE() then purityList(exp.elements);
      case RECORD() then purityList(exp.elements);
      case CALL() then Call.purity(exp.call);
      case SIZE()
        then if isSome(exp.dimIndex) then purity(Util.getOption(exp.dimIndex)) else Purity.PURE;

      case END() then Purity.PURE;
      case BINARY() then Prefixes.purityMin(purity(exp.exp1), purity(exp.exp2));
      case UNARY() then purity(exp.exp);
      case LBINARY() then Prefixes.purityMin(purity(exp.exp1), purity(exp.exp2));
      case LUNARY() then purity(exp.exp);
      case RELATION() then Prefixes.purityMin(purity(exp.exp1), purity(exp.exp2));
      case IF() then Prefixes.purityMin(purity(exp.condition),
                       Prefixes.purityMin(purity(exp.trueBranch), purity(exp.falseBranch)));
      case CAST() then purity(exp.exp);
      case BOX() then purity(exp.exp);
      case UNBOX() then purity(exp.exp);
      case SUBSCRIPTED_EXP()
        then Prefixes.purityMin(purity(exp.exp), Subscript.purityList(exp.subscripts));
      case TUPLE_ELEMENT() then purity(exp.tupleExp);
      case RECORD_ELEMENT() then purity(exp.recordExp);
      case MUTABLE() then purity(Mutable.access(exp.exp));
      case EMPTY() then Purity.PURE;
      case PARTIAL_FUNCTION_APPLICATION() then Purity.PURE;
      case FILENAME() then Purity.PURE;
      else
        algorithm
          Error.assertion(false, getInstanceName() + " got unknown expression.", sourceInfo());
        then
          fail();
    end match;
  end purity;

  function purityArray
    input array<Expression> expl;
    input output Purity pur = Purity.PURE;
  algorithm
    for e in expl loop
      pur := Prefixes.purityMin(pur, purity(e));
    end for;
  end purityArray;

  function purityList
    input list<Expression> expl;
    input output Purity pur = Purity.PURE;
  algorithm
    for e in expl loop
      pur := Prefixes.purityMin(pur, purity(e));
    end for;
  end purityList;

  function makeMutable
    input Expression exp;
    output Expression outExp;
  algorithm
    outExp := MUTABLE(Mutable.create(exp));
  end makeMutable;

  function makeImmutable
    input Expression exp;
    output Expression outExp;
  algorithm
    outExp := match exp
      case MUTABLE() then Mutable.access(exp.exp);
      else exp;
    end match;
  end makeImmutable;

  function isMutable
    input Expression exp;
    output Boolean isMutable;
  algorithm
    isMutable := match exp
      case MUTABLE() then true;
      else false;
    end match;
  end isMutable;

  function updateMutable
    input Expression mutableExp;
    input Expression value;
  protected
    Mutable<Expression> exp_ptr;
  algorithm
    MUTABLE(exp = exp_ptr) := mutableExp;
    Mutable.update(exp_ptr, value);
  end updateMutable;

  function applyMutable
    input Expression mutableExp;
    input FuncType func;

    partial function FuncType
      input output Expression exp;
    end FuncType;
  protected
    Mutable<Expression> exp_ptr;
  algorithm
    MUTABLE(exp = exp_ptr) := mutableExp;
    Mutable.update(exp_ptr, func(Mutable.access(exp_ptr)));
  end applyMutable;

  function isEmpty
    input Expression exp;
    output Boolean empty;
  algorithm
    empty := match exp
      case EMPTY() then true;
      else false;
    end match;
  end isEmpty;

  function isEnd
    input Expression exp;
    output Boolean isend;
  algorithm
    isend := match exp
      case END() then true;
      else false;
    end match;
  end isEnd;

  function enumIndexExp
    input Expression enumExp;
    output Expression indexExp;
  algorithm
    indexExp := match enumExp
      case ENUM_LITERAL() then INTEGER(enumExp.index);
      else CALL(Call.makeTypedCall(
        NFBuiltinFuncs.INTEGER_ENUM, {enumExp}, variability(enumExp), Purity.PURE));
    end match;
  end enumIndexExp;

  function toScalar
    input Expression exp;
    output Expression outExp;
  algorithm
    outExp := match exp
      case ARRAY()
        guard arrayLength(exp.elements) == 1
        then toScalar(arrayGet(exp.elements, 1));
      else exp;
    end match;
  end toScalar;

  function tupleElement
    input Expression exp;
    input Type ty;
    input Integer index;
    output Expression tupleElem;
  algorithm
    tupleElem := match exp
      local
        Type ety;

      case TUPLE() then listGet(exp.elements, index);

      case ARRAY()
        algorithm
          ety := Type.unliftArray(ty);
          exp.elements := Array.map(exp.elements, function tupleElement(ty = ety, index = index));
        then
          exp;

      case SUBSCRIPTED_EXP(split = true)
        then mapSplitExpressions(exp, function tupleElement(ty = ty, index = index));

      else TUPLE_ELEMENT(exp, index, ty);
    end match;
  end tupleElement;

  function recordElement
    "Returns the field with the given name in a record expression. If the
     expression is an array it will return the equivalent of calling the
     function on each element of the array."
    input String elementName;
    input Expression recordExp;
    output Expression outExp;
  algorithm
    outExp := match recordExp
      local
        InstNode node;
        Class cls;
        ClassTree cls_tree;
        Type ty;
        Integer index;
        list<Expression> expl;
        ComponentRef cref;
        array<Expression> arr;

      case RECORD(ty = Type.COMPLEX(cls = node))
        algorithm
          cls := InstNode.getClass(node);
          index := Class.lookupComponentIndex(elementName, cls);
        then
          listGet(recordExp.elements, index);

      case CREF()
        algorithm
          Type.COMPLEX(cls = node) := Type.arrayElementType(recordExp.ty);
          cls_tree := Class.classTree(InstNode.getClass(node));
          (node, false) := ClassTree.lookupElement(elementName, cls_tree);
          ty := InstNode.getType(node);
          cref := ComponentRef.prefixCref(node, ty, {}, recordExp.cref);
          ty := Type.liftArrayLeftList(ty, Type.arrayDims(recordExp.ty));
        then
          CREF(ty, cref);

      case ARRAY(ty = Type.ARRAY(elementType = Type.COMPLEX(cls = node)))
        guard arrayEmpty(recordExp.elements)
        algorithm
          cls := InstNode.getClass(node);
          index := Class.lookupComponentIndex(elementName, cls);
          ty := InstNode.getType(Class.nthComponent(index, cls));
          ty := Type.liftArrayLeftList(ty, Type.arrayDims(recordExp.ty));
        then
          makeEmptyArray(ty);

      case ARRAY(ty = Type.ARRAY(elementType = Type.COMPLEX(cls = node)))
        algorithm
          index := Class.lookupComponentIndex(elementName, InstNode.getClass(node));
          arr := Array.map(recordExp.elements, function nthRecordElement(index = index));
          ty := Type.liftArrayLeft(typeOf(arrayGet(arr, 1)),
                                   Dimension.fromInteger(arrayLength(arr)));
        then
          makeArray(ty, arr, recordExp.literal);

      case SUBSCRIPTED_EXP()
        algorithm
          outExp := recordElement(elementName, recordExp.exp);
          ty := Type.subscript(typeOf(outExp), recordExp.subscripts);
        then
          SUBSCRIPTED_EXP(outExp, recordExp.subscripts, ty, recordExp.split);

      case EMPTY() then fail();

      else
        algorithm
          ty := typeOf(recordExp);
          Type.COMPLEX(cls = node) := Type.arrayElementType(ty);
          cls := InstNode.getClass(node);
          index := Class.lookupComponentIndex(elementName, cls);
          ty := Type.liftArrayLeftList(
            InstNode.getType(Class.nthComponent(index, cls)),
            Type.arrayDims(ty));
        then
          RECORD_ELEMENT(recordExp, index, elementName, ty);

    end match;
  end recordElement;

  function nthRecordElement
    "Returns the nth field of a record expression. If the expression is an array
     it will return an array with the nth field in each array element."
    input Integer index;
    input Expression recordExp;
    output Expression outExp;
  algorithm
    outExp := match recordExp
      local
        InstNode node;
        list<Expression> expl;
        Type ty;
        array<Expression> arr;

      case RECORD() then listGet(recordExp.elements, index);

      case CREF()
        algorithm
          Type.COMPLEX(cls = node) := Type.arrayElementType(typeOf(recordExp));
          node := Class.nthComponent(index, InstNode.getClass(node));
        then
          fromCref(ComponentRef.prefixCref(node, InstNode.getType(node), {}, recordExp.cref));

      case ARRAY(ty = Type.ARRAY(elementType = Type.COMPLEX(cls = node)))
        guard arrayEmpty(recordExp.elements)
        then makeEmptyArray(InstNode.getType(Class.nthComponent(index, InstNode.getClass(node))));

      case ARRAY()
        algorithm
          arr := Array.map(recordExp.elements, function nthRecordElement(index = index));
          ty := Type.liftArrayLeft(typeOf(arrayGet(arr, 1)), listHead(Type.arrayDims(recordExp.ty)));
        then
          makeArray(ty, arr);

      case RECORD_ELEMENT(ty = Type.ARRAY(elementType = Type.COMPLEX(cls = node)))
        algorithm
          node := Class.nthComponent(index, InstNode.getClass(node));
        then
          RECORD_ELEMENT(recordExp, index, InstNode.name(node),
                         Type.liftArrayLeftList(InstNode.getType(node), Type.arrayDims(recordExp.ty)));

      case SUBSCRIPTED_EXP()
        algorithm
          outExp := nthRecordElement(index, recordExp.exp);
          ty := Type.subscript(typeOf(outExp), recordExp.subscripts);
        then
          SUBSCRIPTED_EXP(outExp, recordExp.subscripts, ty, recordExp.split);

      else
        algorithm
          Type.COMPLEX(cls = node) := typeOf(recordExp);
          node := Class.nthComponent(index, InstNode.getClass(node));
        then
          RECORD_ELEMENT(recordExp, index, InstNode.name(node), InstNode.getType(node));

    end match;
  end nthRecordElement;

  function retype
    input output Expression exp;
  algorithm
    () := match exp
      local
        list<Dimension> dims;
        Type ty;

      case RANGE()
        algorithm
          exp.ty := TypeCheck.getRangeType(exp.start, exp.step, exp.stop,
            typeOf(exp.start), AbsynUtil.dummyInfo);
        then
          ();

      case CALL(call = Call.TYPED_ARRAY_CONSTRUCTOR())
        algorithm
          exp.call := Call.retype(exp.call);
        then
          ();

      else
        algorithm
          ty := typeOf(exp);

          if Type.isConditionalArray(ty) then
            ty := Type.simplifyConditionalArray(ty);
            exp := setType(ty, exp);
          end if;
        then
          ();

    end match;
  end retype;

  function nthEnumLiteral
    input Type ty;
    input Integer n;
    output Expression exp;
  algorithm
    exp := ENUM_LITERAL(ty, Type.nthEnumLiteral(ty, n), n);
  end nthEnumLiteral;

  function createIterationRanges
    input output Expression exp;
    input list<tuple<InstNode, Expression>> iterators;
          output list<Expression> ranges = {};
          output list<Mutable<Expression>> iters = {};
  protected
    InstNode node;
    Expression range;
    Mutable<Expression> iter;
  algorithm
    for i in iterators loop
      (node, range) := i;
      iter := Mutable.create(INTEGER(0));
      ranges := list(replaceIterator(r, node, MUTABLE(iter)) for r in ranges);
      exp := replaceIterator(exp, node, MUTABLE(iter));
      iters := iter :: iters;
      ranges := range :: ranges;
    end for;
  end createIterationRanges;

  function foldReduction
    input Expression exp;
    input list<tuple<InstNode, Expression>> iterators;
    input Expression foldExp;
    input MapFn mapFn;
    input FoldFn foldFn;
    output Expression result;

    partial function MapFn
      input output Expression exp;
    end MapFn;

    partial function FoldFn
      input Expression exp1;
      input Expression exp2;
      output Expression result;
    end FoldFn;
  protected
    InstNode node;
    Expression e, range;
    Mutable<Expression> iter;
    list<Expression> ranges = {};
    list<Mutable<Expression>> iters = {};
  algorithm
    (e, ranges, iters) := createIterationRanges(exp, iterators);
    result := foldReduction2(e, ranges, iters, foldExp, mapFn, foldFn);
  end foldReduction;

  function foldReduction2
    input Expression exp;
    input list<Expression> ranges;
    input list<Mutable<Expression>> iterators;
    input Expression foldExp;
    input MapFn mapFn;
    input FoldFn foldFn;
    output Expression result;

    partial function MapFn
      input output Expression exp;
    end MapFn;

    partial function FoldFn
      input Expression exp1;
      input Expression exp2;
      output Expression result;
    end FoldFn;
  protected
    Expression range, value;
    list<Expression> ranges_rest, el;
    Mutable<Expression> iter;
    list<Mutable<Expression>> iters_rest;
    ExpressionIterator range_iter;
  algorithm
    if listEmpty(ranges) then
      result := foldFn(foldExp, mapFn(exp));
    else
      range :: ranges_rest := ranges;
      range := Ceval.evalExp(range);
      iter :: iters_rest := iterators;
      range_iter := ExpressionIterator.fromExp(range);
      result := foldExp;

      while ExpressionIterator.hasNext(range_iter) loop
        (range_iter, value) := ExpressionIterator.next(range_iter);
        Mutable.update(iter, value);
        result := foldReduction2(exp, ranges_rest, iters_rest, result, mapFn, foldFn);
      end while;
    end if;
  end foldReduction2;

  function isPure
    input Expression exp;
    output Boolean isPure;
  algorithm
    isPure := match exp
      case CREF() then not ComponentRef.isIterator(exp.cref);
      case CALL()
        then match AbsynUtil.pathFirstIdent(Call.functionName(exp.call))
          case "Connections" then false;
          case "cardinality" then false;
          else not Call.isImpure(exp.call);
        end match;
      else true;
    end match;
  end isPure;

  function containsCref
    input Expression exp;
    input ComponentRef cref;
    output Boolean b;
  algorithm
    b := fold(exp, function isCrefEqual(cref = cref), false);
  end containsCref;

  function isCrefEqual
    input Expression exp;
    input output Boolean b;
    input ComponentRef cref;
  algorithm
    b := match (b, exp)
      case (false, CREF()) then ComponentRef.isEqual(exp.cref, cref);
      else b;
    end match;
  end isCrefEqual;

  function filterSplitIndices
    input output Expression exp;
    input InstNode node;
  protected
    Expression e;
    list<Subscript> subs;
  algorithm
    exp := match exp
      case SUBSCRIPTED_EXP(exp = e, subscripts = subs)
        algorithm
          subs := list(s for s guard not filterSplitIndices2(s, node) in subs);
        then
          if listEmpty(subs) then
            exp.exp
          elseif Type.isUnknown(exp.ty) then
            SUBSCRIPTED_EXP(exp.exp, subs, exp.ty, List.any(subs, Subscript.isSplit))
          else
            applySubscripts(subs, exp.exp);

      else exp;
    end match;
  end filterSplitIndices;

  function filterSplitIndices2
    input Subscript sub;
    input InstNode node;
    output Boolean matching;
  algorithm
    matching := match sub
      case Subscript.SPLIT_INDEX() then InstNode.refEqual(sub.node, node);
      case Subscript.SPLIT_PROXY() then InstNode.refEqual(sub.parent, node);
      else false;
    end match;
  end filterSplitIndices2;

  function expandSplitIndices
    "Replaces split indices in a subscripted expression with : subscripts."
    input Expression exp;
    output Expression outExp;
  algorithm
    outExp := match exp
      case SUBSCRIPTED_EXP()
        then applySubscripts(Subscript.expandSplitIndices(exp.subscripts, {}), exp.exp);

      case CREF()
        algorithm
          exp.cref := ComponentRef.expandSplitSubscripts(exp.cref);
        then
          exp;

      else exp;
    end match;
  end expandSplitIndices;

  function expandNonListedSplitIndices
    "Replaces split indices in a subscripted expression with : subscripts,
     except for indices that reference nodes in the given list."
    input Expression exp;
    input list<InstNode> indicesToKeep;
    output Expression outExp;
  algorithm
    outExp := match exp
      case SUBSCRIPTED_EXP(split = true)
        then applySubscripts(Subscript.expandSplitIndices(exp.subscripts, indicesToKeep), exp.exp);
      else exp;
    end match;
  end expandNonListedSplitIndices;

  function isSplitSubscriptedExp
    input Expression exp;
    output Boolean split;
  algorithm
    split := match exp
      case SUBSCRIPTED_EXP(split = split) then split;
      else false;
    end match;
  end isSplitSubscriptedExp;

  function mapSplitExpressions
    input Expression exp;
    input Func func;
    output Expression outExp;

    partial function Func
      input output Expression exp;
    end Func;
  protected
    Option<UnorderedMap<Subscript, Expression>> osub_repls;
    UnorderedMap<Subscript, Expression> sub_repls;
    list<Subscript> subs;
    list<Expression> sub_exps, dim_sizes;
  algorithm
    (outExp, osub_repls) := mapFold(exp, replaceSplitSubscripts, NONE());

    if isNone(osub_repls) then
      outExp := func(exp);
    else
      SOME(sub_repls) := osub_repls;
      subs := UnorderedMap.keyList(sub_repls);
      sub_exps := UnorderedMap.valueList(sub_repls);
      dim_sizes := list(Subscript.splitIndexDimExp(s) for s in subs);
      dim_sizes := list(replaceSplitSubscripts(d, SOME(sub_repls)) for d in dim_sizes);
      outExp := mapSplitExpressions2(outExp, dim_sizes, sub_exps, func);
      outExp := applySubscripts(subs, outExp);
    end if;
  end mapSplitExpressions;

  function replaceSplitSubscripts
    input output Expression exp;
    input output Option<UnorderedMap<Subscript, Expression>> subRepls;
  algorithm
    exp := match exp
      local
        list<Subscript> subs;

      case SUBSCRIPTED_EXP(split = true)
        algorithm
          (subs, subRepls) := List.mapFold(exp.subscripts, replaceSplitSubscripts2, subRepls);
        then
          applySubscripts(subs, exp.exp);

      else exp;
    end match;
  end replaceSplitSubscripts;

  function replaceSplitSubscripts2
    input output Subscript subscript;
    input output Option<UnorderedMap<Subscript, Expression>> subRepls;
  protected
    Expression sub_exp;
    UnorderedMap<Subscript, Expression> sub_repls;
  algorithm
    subscript := match subscript
      case Subscript.SPLIT_INDEX()
        algorithm
          if isSome(subRepls) then
            SOME(sub_repls) := subRepls;
          else
            sub_repls := UnorderedMap.new<Expression>(Subscript.hash, Subscript.isEqual);
            subRepls := SOME(sub_repls);
          end if;

          sub_exp := makeMutable(INTEGER(0));
          sub_exp := UnorderedMap.tryAdd(subscript, sub_exp, sub_repls);
        then
          Subscript.INDEX(sub_exp);

      else subscript;
    end match;
  end replaceSplitSubscripts2;

  function mapSplitExpressions2
    input Expression exp;
    input list<Expression> dimSizes;
    input list<Expression> subExps;
    input Func func;
    output Expression outExp;

    partial function Func
      input output Expression exp;
    end Func;
  protected
    Expression dim_size;
    list<Expression> rest_dims;
    Integer dim_size_int;
    Expression sub_exp;
    list<Expression> rest_subs;
    array<Expression> expl;
    Type ty;
  algorithm
    if listEmpty(dimSizes) then
      outExp := map(exp, mapSplitExpressions3);
      outExp := func(outExp);
    else
      dim_size :: rest_dims := dimSizes;
      dim_size_int := toInteger(Ceval.evalExp(dim_size));
      sub_exp :: rest_subs := subExps;
      expl := arrayCreateNoInit(dim_size_int, exp);

      for i in 1:dim_size_int loop
        updateMutable(sub_exp, INTEGER(i));
        arrayUpdateNoBoundsChecking(expl, i,
          mapSplitExpressions2(exp, rest_dims, rest_subs, func));
      end for;

      ty := typeOf(if arrayEmpty(expl) then exp else arrayGet(expl, 1));
      outExp := makeExpArray(expl, ty, Array.all(expl, isLiteral));
    end if;
  end mapSplitExpressions2;

  function mapSplitExpressions3
    input output Expression exp;
  protected
    list<Subscript> subs;
  algorithm
    exp := match exp
      case MUTABLE() then Mutable.access(exp.exp);

      case SUBSCRIPTED_EXP(subscripts = subs)
        then applySubscripts(subs, exp.exp);

      else exp;
    end match;
  end mapSplitExpressions3;

  function mapCrefScalars
    "Takes a cref expression and applies a function to each scalar cref,
     creating a new expression with the same dimensions as the given cref.
       Ex: mapCrefScalars(/*Real[2, 2]*/ x, ComponentRef.toString) =>
           {{'x[1, 1]', 'x[1, 2]'}, {'x[2, 1]', 'x[2, 2]'}}"
    input Expression crefExp;
    input MapFn mapFn;
    output Expression outExp;

    partial function MapFn
      input ComponentRef cref;
      output Expression exp;
    end MapFn;
  algorithm
    outExp := ExpandExp.expand(crefExp);
    outExp := mapCrefScalars2(outExp, mapFn);
  end mapCrefScalars;

  function mapCrefScalars2
    input Expression exp;
    input MapFn mapFn;
    output Expression outExp;

    partial function MapFn
      input ComponentRef cref;
      output Expression exp;
    end MapFn;
  protected
    list<Expression> expl;
    Type ty;
    Boolean literal;
    ComponentRef cref;
    array<Expression> arr;
  algorithm
    outExp := match exp
      case ARRAY()
        guard not arrayEmpty(exp.elements)
        algorithm
          arr := Array.map(exp.elements, function mapCrefScalars2(mapFn = mapFn));
          ty := typeOf(arrayGet(arr, 1));
          literal := Array.all(arr, isLiteral);
        then
          makeExpArray(arr, ty, literal);

      case CREF() then mapFn(exp.cref);
      else exp;
    end match;
  end mapCrefScalars2;

  function isFunctionPointer
    input Expression exp;
    output Boolean res;
  algorithm
    res := match exp
      case CREF(ty = Type.FUNCTION()) then true;
      case PARTIAL_FUNCTION_APPLICATION() then true;
      else false;
    end match;
  end isFunctionPointer;

  function isConnector
    "Returns true if the expression is a component reference that refers to a
     connector, otherwise false."
    input Expression exp;
    output Boolean res;
  protected
    InstNode node;
  algorithm
    res := match exp
      case CREF()
        algorithm
          node := ComponentRef.node(exp.cref);
        then
          InstNode.isComponent(node) and InstNode.isConnector(node);

      else false;
    end match;
  end isConnector;

  function isComponentExpression
    "Returns true if the expression is a component reference that refers to an
     actual component (and not e.g. a function), otherwise false"
    input Expression exp;
    output Boolean res;
  algorithm
    res := match exp
      case CREF()
        then ComponentRef.isCref(exp.cref) and
             InstNode.isComponent(ComponentRef.node(exp.cref));

      else false;
    end match;
  end isComponentExpression;

  function clone
    input output Expression exp;
  algorithm
    () := match exp
      case ARRAY()
        algorithm
          exp.elements := arrayCopy(exp.elements);
        then
          ();
      else ();
    end match;
  end clone;

  function toJSON
    input Expression exp;
    output JSON json;
  protected
    function dump_arg
      input String name;
      input Expression arg;
      output JSON json = JSON.emptyObject();
    algorithm
      json := JSON.addPair("name", JSON.makeString(name), json);
      json := JSON.addPair("value", toJSON(arg), json);
    end dump_arg;
  algorithm
    json := match exp
      case INTEGER() then JSON.makeInteger(exp.value);
      case REAL() then JSON.makeNumber(exp.value);
      case STRING() then JSON.makeString(exp.value);
      case BOOLEAN() then JSON.makeBoolean(exp.value);
      case ENUM_LITERAL()
        algorithm
          json := JSON.emptyObject();
          json := JSON.addPair("$kind", JSON.makeString("enum"), json);
          json := JSON.addPair("name", JSON.makeString(Expression.toString(exp)), json);
          json := JSON.addPair("index", JSON.makeInteger(exp.index), json);
        then
          json;

      case CLKCONST()
        then ClockKind.toJSON(exp.clk);

      case CREF() then ComponentRef.toJSON(exp.cref);

      case TYPENAME()
        algorithm
          json := JSON.emptyObject();
          json := JSON.addPair("$kind", JSON.makeString("typename"), json);
          json := JSON.addPair("name", JSON.makeString(Type.toString(exp.ty)), json);
        then
          json;

      case ARRAY()
        algorithm
          json := JSON.emptyArray(arrayLength(exp.elements));
          for e in exp.elements loop
            json := JSON.addElement(toJSON(e), json);
          end for;
        then
          json;

      case RANGE()
        algorithm
          json := JSON.emptyObject();
          json := JSON.addPair("$kind", JSON.makeString("range"), json);
          json := JSON.addPair("start", toJSON(exp.start), json);

          if isSome(exp.step) then
            json := JSON.addPair("step", toJSON(Util.getOption(exp.step)), json);
          end if;

          json := JSON.addPair("stop", toJSON(exp.stop), json);
        then
          json;

      case TUPLE()
        algorithm
          json := JSON.emptyObject();
          json := JSON.addPair("$kind", JSON.makeString("tuple"), json);
          json := JSON.addPair("elements",
            JSON.makeArray(list(toJSON(e) for e in exp.elements)), json);
        then
          json;

      case RECORD()
        algorithm
          json := JSON.emptyObject();
          json := JSON.addPair("$kind", JSON.makeString("record"), json);
          json := JSON.addPair("name", JSON.makeString(AbsynUtil.pathString(exp.path)), json);
          json := JSON.addPair("elements",
            JSON.makeArray(list(toJSON(e) for e in exp.elements)), json);
        then
          json;

      case CALL()
        then Call.toJSON(exp.call);

      case SIZE()
        algorithm
          json := JSON.emptyObject();
          json := JSON.addPair("$kind", JSON.makeString("call"), json);
          json := JSON.addPair("name", JSON.makeString("size"), json);

          if isSome(exp.dimIndex) then
            JSON.addPair("arguments",
              JSON.makeArray({toJSON(exp.exp), toJSON(Util.getOption(exp.dimIndex))}), json);
          else
            JSON.addPair("arguments", JSON.makeArray({toJSON(exp.exp)}), json);
          end if;
        then
          json;

      case BINARY()
        algorithm
          json := JSON.emptyObject();
          json := JSON.addPair("$kind", JSON.makeString("binary_op"), json);
          json := JSON.addPair("lhs", toJSON(exp.exp1), json);
          json := JSON.addPair("op", JSON.makeString(Operator.symbol(exp.operator, spacing = "")), json);
          json := JSON.addPair("rhs", toJSON(exp.exp2), json);
        then
          json;

      case UNARY()
        algorithm
          json := JSON.emptyObject();
          json := JSON.addPair("$kind", JSON.makeString("unary_op"), json);
          json := JSON.addPair("op", JSON.makeString(Operator.symbol(exp.operator, spacing = "")), json);
          json := JSON.addPair("exp", toJSON(exp.exp), json);
        then
          json;

      case LBINARY()
        algorithm
          json := JSON.emptyObject();
          json := JSON.addPair("$kind", JSON.makeString("binary_op"), json);
          json := JSON.addPair("lhs", toJSON(exp.exp1), json);
          json := JSON.addPair("op", JSON.makeString(Operator.symbol(exp.operator, spacing = "")), json);
          json := JSON.addPair("rhs", toJSON(exp.exp2), json);
        then
          json;

      case LUNARY()
        algorithm
          json := JSON.emptyObject();
          json := JSON.addPair("$kind", JSON.makeString("unary_op"), json);
          json := JSON.addPair("op", JSON.makeString(Operator.symbol(exp.operator, spacing = "")), json);
          json := JSON.addPair("exp", toJSON(exp.exp), json);
        then
          json;

      case RELATION()
        algorithm
          json := JSON.emptyObject();
          json := JSON.addPair("$kind", JSON.makeString("binary_op"), json);
          json := JSON.addPair("lhs", toJSON(exp.exp1), json);
          json := JSON.addPair("op", JSON.makeString(Operator.symbol(exp.operator, spacing = "")), json);
          json := JSON.addPair("rhs", toJSON(exp.exp2), json);
        then
          json;

      case MULTARY()
        algorithm
          json := JSON.emptyObject();
          json := JSON.addPair("$kind", JSON.makeString("multary_op"), json);
          json := JSON.addPair("args",
            JSON.makeArray(list(toJSON(a) for a in exp.arguments)), json);
          json := JSON.addPair("inv_args",
            JSON.makeArray(list(toJSON(a) for a in exp.inv_arguments)), json);
          json := JSON.addPair("op", JSON.makeString(Operator.symbol(exp.operator, spacing = "")), json);
        then
          json;

      case IF()
        algorithm
          json := JSON.emptyObject();
          json := JSON.addPair("$kind", JSON.makeString("if"), json);
          json := JSON.addPair("condition", toJSON(exp.condition), json);
          json := JSON.addPair("true", toJSON(exp.trueBranch), json);
          json := JSON.addPair("false", toJSON(exp.falseBranch), json);
        then
          json;

      case CAST() then toJSON(exp.exp);
      case BOX() then toJSON(exp.exp);
      case UNBOX() then toJSON(exp.exp);

      case SUBSCRIPTED_EXP()
        algorithm
          json := JSON.emptyObject();
          json := JSON.addPair("$kind", JSON.makeString("sub"), json);
          json := JSON.addPair("exp", toJSON(exp.exp), json);
          json := JSON.addPair("subscripts", Subscript.toJSONList(exp.subscripts), json);
        then
          json;

      case TUPLE_ELEMENT()
        algorithm
          json := JSON.emptyObject();
          json := JSON.addPair("$kind", JSON.makeString("tuple_element"), json);
          json := JSON.addPair("exp", toJSON(exp.tupleExp), json);
          json := JSON.addPair("index", JSON.makeInteger(exp.index), json);
        then
          json;

      case RECORD_ELEMENT()
        algorithm
          json := JSON.emptyObject();
          json := JSON.addPair("$kind", JSON.makeString("record_element"), json);
          json := JSON.addPair("exp", toJSON(exp.recordExp), json);
          json := JSON.addPair("index", JSON.makeInteger(exp.index), json);
          json := JSON.addPair("field", JSON.makeString(exp.fieldName), json);
        then
          json;

      case PARTIAL_FUNCTION_APPLICATION()
        algorithm
          json := JSON.emptyObject();
          json := JSON.addPair("$kind", JSON.makeString("function"), json);
          json := JSON.addPair("name", JSON.makeString(ComponentRef.toString(exp.fn)), json);
          json := JSON.addPair("arguments", JSON.makeArray(
            list(dump_arg(name, arg) threaded for arg in exp.args, name in exp.argNames)), json);
        then
          json;

      case FILENAME() then JSON.makeString(exp.filename);

      else JSON.makeString(toString(exp));
    end match;
  end toJSON;

  function tupleElements
    input Expression exp;
    output list<Expression> expl;
  algorithm
    expl := match exp
      case TUPLE() then exp.elements;
      else {exp};
    end match;
  end tupleElements;

  function wrapCall
    "wrapper function to apply a Call function"
    input output Expression exp;
    input callFun fun;
    partial function callFun
      input output Call call;
    end callFun;
  algorithm
    exp := match exp
      case CALL() algorithm
        exp.call := fun(exp.call);
      then exp;
      else exp;
    end match;
  end wrapCall;

  function repairOperator
    input output Expression exp;
  algorithm
    exp := match exp
      case BINARY() algorithm
        exp.operator := Operator.repairBinary(exp.operator, typeOf(exp.exp1), typeOf(exp.exp2));
      then exp;

      case MULTARY() algorithm
        exp.operator := Operator.repairMultary(exp.operator, list(typeOf(e) for e in listAppend(exp.arguments, exp.inv_arguments)));
      then exp;

      else exp;
    end match;
  end repairOperator;

  function makeUnary
    input Operator op;
    input Expression exp;
    output Expression unaryExp;
  algorithm
    if op.op == NFOperator.Op.ADD then
      unaryExp := exp;
    elseif op.op == NFOperator.Op.UMINUS then
      unaryExp := negate(exp);
    else
      unaryExp := UNARY(op, exp);
    end if;
  end makeUnary;

annotation(__OpenModelica_Interface="frontend");
end NFExpression;