Module Simula

Package simula.compiler.syntaxClass.statement

Class SwitchStatement

java.lang.Object

simula.compiler.syntaxClass.SyntaxClass

simula.compiler.syntaxClass.statement.Statement

simula.compiler.syntaxClass.statement.SwitchStatement

public final class SwitchStatement
extends Statement

Switch Statement. This is a S-PORT extension to the language.

 
 Syntax:
 
 switch-statement = SWITCH ( lowKey : hiKey ) switchKey BEGIN { switch-case } [ none-case ] END [ otherwise-case ]
 
      switch-case = WHEN caseKey-list do statement ;
      
      none-case   = WHEN NONE do statement ;
      
      otherwise-case = OTHERWISE statement ;
      
         caseKey-list = caseKey { , caseKey }
      
            caseKey = caseConstant  | caseConstant : caseConstant
            
               caseConstant = integer-or-character-constant
      
      lowKey = integer-or-character-expression
      hiKey = integer-or-character-expression
      switchKey = integer-or-character-expression

 Translated into a Java Switch Statement with break after each statement.
 
 Example:
 
   switch(lowkey:hikey) key
   begin
      when 0 do statement-0 ;
      ...
      when none do statement-e ;
   end
   
   Is compiled into Java-code:
   
   if(key < lowkey || key > hikey) throw new RTS_SimulaRuntimeError("Switch key outside key interval");
   switch(key) {
       case 0: statement-0; break;
       ...
       default: statement-e; break;
   }
   
 

Link to GitHub: Source File.

Author:

Øystein Myhre Andersen

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private class	SwitchStatement.SwitchInterval	Utility class SwitchInterval
private class	SwitchStatement.WhenPart	Utility class WhenPart.

Field Summary

Fields

Modifier and Type	Field	Description
private final Expression	hiKey	The high key
private final Expression	lowKey	The low key.
private final Vector<SwitchStatement.WhenPart>	switchCases	The list of When parts
private Expression	switchKey	The switchKey

Fields inherited from class simula.compiler.syntaxClass.SyntaxClass

lineNumber

Constructor Summary

Constructors

Constructor	Description
SwitchStatement(int line)	Create a new SwitchStatement.

Method Summary

Modifier and Type	Method	Description
void	doChecking()	Perform semantic checking.
void	doJavaCoding()	Output Java code.
private SwitchStatement.SwitchInterval	expectCasePair()	Parse Utility: Expect case pair.
void	print(int indent)	Utility print method.
void	printTree(int indent)	Utility print syntax tree method.
String	toString()

Methods inherited from class simula.compiler.syntaxClass.statement.Statement

expectStatement

Methods inherited from class simula.compiler.syntaxClass.SyntaxClass

ASSERT_SEMANTICS_CHECKED, doDeclarationCoding, edIndent, edTreeIndent, IS_SEMANTICS_CHECKED, SET_SEMANTICS_CHECKED, toJavaCode

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Details

lowKey

private final Expression lowKey

The low key.

hiKey

private final Expression hiKey

The high key

switchKey

private Expression switchKey

The switchKey

switchCases

private final Vector<SwitchStatement.WhenPart> switchCases

The list of When parts

Constructor Details

SwitchStatement

SwitchStatement(int line)

Create a new SwitchStatement.

Parameters:

line - the source line number

Method Details

expectCasePair

private SwitchStatement.SwitchInterval expectCasePair()

Parse Utility: Expect case pair.

Returns:

the resulting SwitchInterval

doChecking

public void doChecking()

Description copied from class: SyntaxClass

Perform semantic checking.

This must be redefined in every subclass.

Overrides:

doChecking in class SyntaxClass

doJavaCoding

public void doJavaCoding()

Description copied from class: SyntaxClass

Output Java code.

Overrides:

doJavaCoding in class Statement

print

public void print(int indent)

Description copied from class: SyntaxClass

Utility print method.

Overrides:

print in class SyntaxClass

Parameters:

indent - number of spaces leading the line

printTree

public void printTree(int indent)

Description copied from class: SyntaxClass

Utility print syntax tree method.

Overrides:

printTree in class SyntaxClass

Parameters:

indent - number of spaces leading the lines

toString

public String toString()

Overrides:

toString in class Object