UglyExpressions.mc4

// (c) https://github.com/MontiCore/monticore
package de.monticore.expressions;

/* This is a MontiCore stable grammar.
 * Adaptations -- if any -- are conservative. */

import de.monticore.expressions.*;
import de.monticore.types.*;

/**
 * This grammar defines expressions that are considered "ugly"
 * in terms of use, e.g.,
 *   instanceof, typecasting, and new Class(...)-constructors.
 * like in 
 *   person instanceof Student
 *   (Student)person
 *   new Person("George")
 * 
 * The reason is that each of them uses explicit types and prevents
 *   easy adaptation and reconfiguration, e.g. for testing.
 *   new-calls e.g. prevent to inject stubs/mocks when testing.
 *   Better: Use the Builder or Factory pattern.
 *
 * The grammar should be omitted e.g. in functional languages, but is
 * present for compatibility with Java-Expressions.
 *
 * This grammar is part of a hierarchy of expression grammars, 
 * which can be found under
 *   https://github.com/MontiCore/monticore/blob/dev/monticore-grammar/
 *                 src/main/grammars/de/monticore/expressions/Expressions.md
*/

component grammar UglyExpressions
          extends MCBasicTypes,
                  ExpressionsBasis {

  /*=================================================================*/

  /**
   * ASTTypeCastExpression casts an expression to a given type
   *   @attribute MCType
   *              type to cast the expression to
   *   @attribute Expression
   *              the expression that should be casted
   */
  TypeCastExpression implements Expression <200> =
    "(" MCType ")" Expression;

  /**
   * InstanceofExpression checks if an expression has a certain type
   *   evaluates to true if the expression has the type given by MCType
   *   otherwise evaluates to false
   *
   *   @attribute Expression
   *              expression whose type is to be checked
   *   @attribute MCType
   *              type against which the expression should be checked
   */
  InstanceofExpression implements Expression <150> =
    Expression "instanceof" MCType;

  CreatorExpression implements Expression <235> =
    "new" Creator;

  interface Creator ;

  ClassCreator implements Creator
    =   MCType Arguments;

  ArrayCreator implements Creator
    =   MCType ArrayDimensionSpecifier;

  interface ArrayDimensionSpecifier ;

  ArrayDimensionByExpression implements ArrayDimensionSpecifier
    =   ("[" Expression "]")+ (dim:"[" "]")*
    ;

}