Module Simula
Package simula.compiler.syntaxClass.expression

Class VariableExpression

java.lang.Object
simula.compiler.syntaxClass.SyntaxClass
simula.compiler.syntaxClass.expression.Expression
simula.compiler.syntaxClass.expression.VariableExpression
public final class VariableExpression extends Expression
Variable. 
 
 Simula Standard: 3.1 Variables
 Simula Standard: 3.1.3. Array elements
 Simula Standard: 3.1.4. Function designators
 
 variable = simple-variable | subscripted-variable | simple-object-expression . variable
 
    simple-object-expression = NONE | variable | function-designator | object-generator
                             | local-object | qualified-object | ( object-expression )
                             
    simple-variable = identifier
 
    subscripted-variable = function-designator | array-element
 
       function-designator = procedure-identifier ( [ actual-parameter-part ] )
  
          actual-parameter-part = actual-parameter { , actual-parameter }
          
             actual-parameter = expression | array-identifier1 
                              | switch-identifier1 | procedure-identifier1
                              
                identifier1 = identifier | remote-identifier
                
                   remote-identifier = simple-object-expression . attribute-identifier
                                     | text-primary . attribute-identifier

       array-element = array-identifier [ subscript-list ]
       
          subscript-list = arithmetic-expression { , arithmetic-expression }
Function designators:

A function designator defines a value which results through the application of a given set of rules defined by a procedure declaration (see 5.4) to a fixed set of actual parameters. The rules governing specification of actual parameters are given in 4.6. Note: Not every procedure declaration defines rules for determining the value of a function designator (cf. 5.4.1).

Array elements:

Subscripted variables designate values which are components of multi- dimensional arrays. Each arithmetic expression of the subscript list occupies one subscript position of the subscripted variable and is called a subscript. The complete list of subscripts is enclosed by the subscript parentheses ( ). The array component referred to by a subscripted variable is specified by the actual value of its subscripts.

Each subscript position acts like a variable of type integer and the evaluation of the subscript is understood to be equivalent to an assignment to this fictitious variable. The value of the subscripted variable is defined only if the actual integer value of each subscript expression is within the associated subscript bounds of the array. A subscript expression value outside its associated bounds causes a run time error.

Link to GitHub: Source File.

Author:
SIMULA Standards Group, Øystein Myhre Andersen

  • Field Details

    • identifier

      public String identifier
      The variable's identifier.

    • meaning

      public Meaning meaning
      The meaning of this variable.

    • remotelyAccessed

      private boolean remotelyAccessed
      Indicates that this variable is remotely accessed.

    • params

      Vector<Expression> params
      The parsed parameters.

    • checkedParams

      public Vector<Expression> checkedParams
      The checked parameters set by doChecking.

  • Constructor Details

    • VariableExpression

      public VariableExpression(String identifier)
      Create a new Variable.
      Parameters:
      identifier - the variable's identifier

  • Method Details

    • hasArguments

      public boolean hasArguments()
      Returns true if this variable has arguments.
      Returns:
      true if this variable has arguments

    • getJavaIdentifier

      String getJavaIdentifier()
      Returns a suitable java identifier for this variable.
      Returns:
      a suitable java identifier

    • setRemotelyAccessed

      void setRemotelyAccessed(Meaning meaning)
      This variable is remotely accessed through 'meaning'.
      Parameters:
      meaning - before dot

    • getMeaning

      Meaning getMeaning()
      Returns the meaning.

      If meaning is not set by setRemotelyAccessed then meaning by identifier will be set.

      Returns:
      the meaning

    • expectVariable

      public static VariableExpression expectVariable(String ident)
      Parse Utility: Expect Variable. 
       Variable  =  Identifier  |  SubscriptedVariable
        SubscriptedVariable  =  Identifier  "("  Expression  {  ,  Expression  }  ")"
      Precondition: Identifier is already read.
      Parameters:
      ident - the variable identifier
      Returns:
      the created Variable

    • getWriteableVariable

      public VariableExpression getWriteableVariable()
      Description copied from class: Expression
      Get a writeable variable.

      This method is redefined in Variable, RemoteVariable and TypeConversion

      Overrides:
      getWriteableVariable in class Expression
      Returns:
      a writeable variable or null

    • doChecking

      public void doChecking()
      Description copied from class: SyntaxClass
      Perform semantic checking.

      This must be redefined in every subclass.

      Overrides:
      doChecking in class SyntaxClass

    • maybeStatement

      public boolean maybeStatement()
      Description copied from class: Expression
      Returns true if this expression may be used as a statement.
      Specified by:
      maybeStatement in class Expression
      Returns:
      true if this expression may be used as a statement

    • toJavaCode

      public String toJavaCode()
      Description copied from class: SyntaxClass
      Generate Java code for this Syntax Class.
      Overrides:
      toJavaCode in class SyntaxClass
      Returns:
      Java code

    • put

      public String put(String rightPart)
      Description copied from class: Expression
      Generate code for putting the value into this Expression
      Overrides:
      put in class Expression
      Parameters:
      rightPart - a evaluated expression.
      Returns:
      the resulting Java code

    • get

      public String get()
      Description copied from class: Expression
      Generate code for getting the value of this Expression
      Overrides:
      get in class Expression
      Returns:
      the resulting Java code

    • doGetELEMENT

      public String doGetELEMENT(String var)
      Coding utility: doGetELEMENT.
      Parameters:
      var - the variable
      Returns:
      a suitable java code

    • doPutELEMENT

      public String doPutELEMENT(String var, String rightPart)
      Coding utility: doPutELEMENT.
      Parameters:
      var - the variable
      rightPart - the right hand side
      Returns:
      a suitable java code

    • editVariable

      private String editVariable(String rightPart)
      Coding Utility: Edit this Variable.
      Parameters:
      rightPart - When destination, this is the right part of the assignment
      Returns:
      the resulting Java source code

    • edIdentifierAccess

      public String edIdentifierAccess(boolean destination)
      Coding utility: Edit identifier access.
      Parameters:
      destination - true if this variable is a destination
      Returns:
      a suitable java code

    • edIdentifierAccess

      private String edIdentifierAccess(String id, boolean destination)
      Coding Utility: Edit identifier access.
      Parameters:
      id - the identifier
      destination - true if destination
      Returns:
      a suitable java code

    • printTree

      public void printTree(int indent)
      Description copied from class: SyntaxClass
      Utility print syntax tree method.
      Overrides:
      printTree in class Expression
      Parameters:
      indent - number of spaces leading the lines

    • toString

      public String toString()
      Overrides:
      toString in class Expression