Class StepUntilElement

java.lang.Object
simula.compiler.syntaxClass.SyntaxClass
simula.compiler.syntaxClass.statement.ForListElement
simula.compiler.syntaxClass.statement.StepUntilElement
public class StepUntilElement extends ForListElement

Utility class: For-list Step until element.

Link to GitHub: Source File.

Author:
Øystein Myhre Andersen

  • Field Details

    • expr2

      Expression expr2
      The second expression.

    • expr3

      Expression expr3
      The third expression.

    • DELTA_SEQU

      private static int DELTA_SEQU
      Used to make deltaID unique.

  • Constructor Details

    • StepUntilElement

      public StepUntilElement(ForStatement forStatement, Expression expr1, Expression expr2, Expression expr3)
      Create a new StepUntilElement.
      Parameters:
      forStatement - the ForStatement
      expr1 - The first expression
      expr2 - The second expression
      expr3 - The third expression

    • StepUntilElement

      private StepUntilElement()
      Default constructor used by Attribute File I/O

  • Method Details

    • doChecking

      public void doChecking()
      Description copied from class: ForListElement
      Perform semantic checking.
      Overrides:
      doChecking in class ForListElement

    • edCode

      public String edCode(String classIdent, Type xType)
      Description copied from class: ForListElement
      Edit Java source code for this ForListElement.
      Overrides:
      edCode in class ForListElement
      Parameters:
      classIdent - Java class identifier
      xType - control variable's type
      Returns:
      the resulting Java source code for this ForListElement

    • isOptimisable

      public ForListElement isOptimisable()
      Description copied from class: ForListElement
      Checks if this ForListElement can be optimized.
      Overrides:
      isOptimisable in class ForListElement
      Returns:
      this ForListElement if it can be optimized

    • doSimplifiedJavaCoding

      public void doSimplifiedJavaCoding()
      Description copied from class: ForListElement
      Perform simplified JavaCoding.
      Overrides:
      doSimplifiedJavaCoding in class ForListElement

    • generalCase

      private void generalCase()

      ClassFile coding utility: generalCase.

      FOR controlVariable := expr1 STEP expr2 UNTIL expr3 DO statement;

According to Simula Standard:

		int/float/double DELTA; // Local

		controlVariable = expr1();
		DELTA = expr2();
		while( sign(DELTA)*(controlVariable-expr3()) <= 0) {
			STATEMENT();
			DELTA = expr2();
			controlVariable = controlVariable + DELTA;
		}  // end while;

    • doSingleElementByteCoding

      public void doSingleElementByteCoding(CodeBuilder codeBuilder)

      ClassFile coding utility: doSingleElementByteCoding.

      FOR controlVariable := expr1 STEP expr2 UNTIL expr3 DO statement;


int/float/double DELTA; // Local

controlVariable = expr1();
DELTA = expr2();
while( sign(DELTA)/// (controlVariable - expr3() ) <= 0) {
		STATEMENT();
		DELTA = expr2();
		controlVariable = controlVariable + DELTA;
}  // end while;


  // controlVariable = expr1();
  aload_0
  aload_0
  invokevirtual #24                 // Method expr1:()I
  putfield      #12                 // Field controlVariable:I

// DELTA = expr2();
  aload_0
  invokevirtual #26                 // Method expr2:()I
  istore_1	   // Local DELTA

TST:
// if(DELTA*(controlVariable-expr3()) > 0) goto END
  iload_1       // Local DELTA
  aload_0
  getfield      #12                 // Field controlVariable:I
  aload_0
  invokevirtual #30                 // Method expr3:()I
  isub
  imul
  ifle          END

// STATEMENT
  aload_0
  invokevirtual #28                 // Method STATEMENT:()V
  
// DELTA = expr2();
  aload_0
  invokevirtual #26                 // Method expr2:()I
  istore_1      // Local DELTA
  
// controlVariable = controlVariable + DELTA;  
  aload_0
  dup
  getfield      #12                 // Field controlVariable:I
  iload_1       // Local DELTA
  iadd
  putfield      #12                 // Field controlVariable:I

  goto          TST
  
END:
      Overrides:
      doSingleElementByteCoding in class ForListElement
      Parameters:
      codeBuilder - the codeBuilder to use.

    • buildByteCode

      public void buildByteCode(CodeBuilder codeBuilder, VariableExpression controlVariable)
      Description copied from class: ForListElement
      Build byte code.
      Overrides:
      buildByteCode in class ForListElement
      Parameters:
      codeBuilder - the codeBuilder to use.
      controlVariable - the ForStatement's controlVariable.

    • toString

      public String toString()
      Overrides:
      toString in class ForListElement

    • writeObject

      public void writeObject(AttributeOutputStream oupt) throws IOException
      Description copied from class: SyntaxClass
      Write a SyntaxClass object to a AttributeOutputStream.
      Overrides:
      writeObject in class ForListElement
      Parameters:
      oupt - the AttributeOutputStream to write to.
      Throws:
      IOException - if something went wrong.

    • readObject

      public static StepUntilElement readObject(AttributeInputStream inpt) throws IOException
      Read and return an object.
      Parameters:
      inpt - the AttributeInputStream to read from
      Returns:
      the object read from the stream.
      Throws:
      IOException - if something went wrong.