[NF] Preserve for loops with -d=-nfScalarize, ticket:5110, ticket:5144

See NFFlatten.flattenEquation to enable this feature.

Belonging to [master]:
  - #2685
  - OpenModelica/OpenModelica-testsuite#1042

Compiler/FrontEnd/DAE.mo

@@ -272,6 +272,16 @@ public uniontype Element
     ElementSource source "the origin of the component/equation/algorithm" ;
   end WHEN_EQUATION;
 
+  record FOR_EQUATION " a for-equation"
+    Type type_ "this is the type of the iterator";
+    Boolean iterIsArray "True if the iterator has an array type, otherwise false.";
+    Ident iter "the iterator variable";
+    Integer index "the index of the iterator variable, to make it unique; used by the new inst";
+    Exp range "range for the loop";
+    list<Element> equations "Equations" ;
+    ElementSource source "the origin of the component/equation/algorithm" ;
+  end FOR_EQUATION;
+
   record IF_EQUATION " an if-equation"
     list<Exp> condition1 "Condition" ;
     list<list<Element>> equations2 "Equations of true branch" ;

Compiler/FrontEnd/DAEDump.mo

@@ -2996,6 +2996,17 @@ algorithm
       then
         str;
 
+    case (DAE.FOR_EQUATION(iter = s, range = e1, equations = xs1, source = src) :: xs, str)
+      equation
+        sourceStr = getSourceInformationStr(src);
+        s1 = ExpressionDump.printExpStr(e1);
+        str = IOStream.appendList(str, {"  for ", s, " in ", s1, " loop\n"});
+        str = dumpEquationsStream(xs1, str);
+        str = IOStream.appendList(str, {"  end for;\n"});
+        str = dumpEquationsStream(xs, str);
+      then
+        str;
+
     case ((DAE.IF_EQUATION(condition1 = {},equations2 = {},equations3 = {}) :: _), str)
       then
         str;

Compiler/FrontEnd/DAEUtil.mo

@@ -424,6 +424,11 @@ algorithm
           DoubleEndedList.push_back(eqs, elt);
         then ();
 
+      case DAE.FOR_EQUATION()
+        algorithm
+          DoubleEndedList.push_back(eqs, elt);
+        then ();
+
       case DAE.IF_EQUATION()
         algorithm
           DoubleEndedList.push_back(eqs, elt);
@@ -4160,6 +4165,15 @@ algorithm
       then
         ();
 
+    case DAE.FOR_EQUATION(range = e1, equations = el)
+      algorithm
+        (new_e1, arg) := func(e1, arg);
+        if not referenceEq(e1, new_e1) then element.range := new_e1; end if;
+        (new_el, arg) := traverseDAEElementList(el, func, arg);
+        if not referenceEq(el, new_el) then element.equations := new_el; end if;
+      then
+        ();
+
     case DAE.COMP(dAElist = el)
       algorithm
         (new_el, arg) := traverseDAEElementList(el, func, arg);
@@ -5152,6 +5166,8 @@ algorithm
         algorithm equations := e :: equations; then ();
       case DAE.IF_EQUATION()
         algorithm equations := e :: equations; then ();
+      case DAE.FOR_EQUATION()
+        algorithm equations := e :: equations; then ();
       case DAE.WHEN_EQUATION()
         algorithm equations := e :: equations; then ();
       case DAE.REINIT()

Compiler/NFFrontEnd/NFConvertDAE.mo

@@ -491,12 +491,8 @@ algorithm
       then
         DAE.Element.ARRAY_EQUATION(dims, e1, e2, eq.source) :: elements;
 
-    // For equations should have been unrolled here.
     case Equation.FOR()
-      algorithm
-        Error.assertion(false, getInstanceName() + " got a for equation", sourceInfo());
-      then
-        fail();
+      then convertForEquation(eq) :: elements;
 
     case Equation.IF()
       then convertIfEquation(eq.branches, eq.source, isInitial = false) :: elements;
@@ -529,6 +525,25 @@ algorithm
   end match;
 end convertEquation;
 
+function convertForEquation
+  input Equation forEquation;
+  output DAE.Element forDAE;
+protected
+  InstNode iterator;
+  Type ty;
+  Expression range;
+  list<Equation> body;
+  list<DAE.Element> dbody;
+  DAE.ElementSource source;
+algorithm
+  Equation.FOR(iterator = iterator, range = SOME(range), body = body, source = source) := forEquation;
+  dbody := convertEquations(body);
+  Component.ITERATOR(ty = ty) := InstNode.component(iterator);
+
+  forDAE := DAE.Element.FOR_EQUATION(Type.toDAE(ty), Type.isArray(ty),
+    InstNode.name(iterator), 0, Expression.toDAE(range), dbody, source);
+end convertForEquation;
+
 function convertIfEquation
   input list<Equation.Branch> ifBranches;
   input DAE.ElementSource source;
@@ -626,12 +641,8 @@ algorithm
       then
         DAE.Element.INITIAL_ARRAY_EQUATION(dims, e1, e2, eq.source) :: elements;
 
-    // For equations should have been unrolled here.
     case Equation.FOR()
-      algorithm
-        Error.assertion(false, getInstanceName() + " got a for equation", sourceInfo());
-      then
-        fail();
+      then convertForEquation(eq) :: elements;
 
     case Equation.IF()
       then convertIfEquation(eq.branches, eq.source, isInitial = true) :: elements;

Compiler/NFFrontEnd/NFFlatten.mo

@@ -724,7 +724,13 @@ algorithm
         Equation.EQUALITY(e1, e2, eq.ty, eq.source) :: equations;
 
     case Equation.FOR()
-      then unrollForLoop(eq, prefix, equations);
+      algorithm
+        if Flags.isSet(Flags.NF_SCALARIZE) then
+          eql := unrollForLoop(eq, prefix, equations);
+        else
+          eql := eq :: equations;
+        end if;
+      then eql;
 
     case Equation.CONNECT()
       algorithm

Compiler/Template/DAEDumpTV.mo

@@ -354,6 +354,16 @@ package DAE
       ElementSource source "the origin of the component/equation/algorithm";
     end WHEN_EQUATION;
 
+    record FOR_EQUATION " a for-equation"
+      Type type_ "this is the type of the iterator";
+      Boolean iterIsArray "True if the iterator has an array type, otherwise false.";
+      Ident iter "the iterator variable";
+      Integer index "the index of the iterator variable, to make it unique; used by the new inst";
+      Exp range "range for the loop";
+      list<Element> equations "Equations" ;
+      ElementSource source "the origin of the component/equation/algorithm" ;
+    end FOR_EQUATION;
+
     record IF_EQUATION " an if-equation"
       list<Exp> condition1 "Condition" ;
       list<list<Element>> equations2 "Equations of true branch" ;

Compiler/Template/DAEDumpTpl.tpl

@@ -619,6 +619,7 @@ match lst
   case COMPLEX_EQUATION(__) then dumpEquation(lhs, rhs, source)
   case DEFINE(__) then dumpDefine(componentRef, exp, source)
   case WHEN_EQUATION(__) then dumpWhenEquation(lst)
+  case FOR_EQUATION(__) then dumpForEquation(lst)
   case IF_EQUATION(__) then dumpIfEquation(condition1, equations2, equations3, source)
   case ASSERT(__) then dumpAssert(condition, message, level, source)
   case INITIAL_ASSERT(__) then dumpAssert(condition, message, level, source)
@@ -729,6 +730,20 @@ match lst
     >>
 end dumpWhenEquation;
 
+template dumpForEquation(DAE.Element lst)
+::=
+match lst
+  case FOR_EQUATION(__) then
+    let range_str = dumpExp(range)
+    let body_str = (equations |> e => dumpEquationElement(e) ;separator="\n")
+    let src_str = dumpSource(source)
+    <<
+    for <%iter%> in <%range_str%> loop
+      <%body_str%>
+    end for<%src_str%>;
+    >>
+end dumpForEquation;
+
 template dumpIfEquation(list<DAE.Exp> conds, list<list<DAE.Element>> branches,
   list<DAE.Element> else_branch, DAE.ElementSource src)
 ::=