Package gnu.expr

Class CaseExp

java.lang.Object

gnu.mapping.PropertySet

gnu.mapping.Procedure

gnu.expr.Expression

gnu.expr.CaseExp

All Implemented Interfaces:

gnu.kawa.format.Printable, Named, SourceLocator, SourceLocator, Locator

public class CaseExp
extends Expression

This class represents a case expression

 case case-key case-clause+
 case case-key case-clause* case-else-clause
     case-key ::= expression
     case-clause ::= ((datum*) expression+)
        | ((datum*) => expression)
     case-else-clause ::= (else  expression+)
        | (else => expression)
 

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	CaseExp.CaseClause	This class represent a clause of the case expression, of the form ((datum*) expression+) or (else expression+)

Nested classes/interfaces inherited from interface gnu.text.SourceLocator

SourceLocator.Simple

Field Summary

Fields inherited from class gnu.expr.Expression

applyMethodExpression, flags, NEXT_AVAIL_FLAG, noExpressions, type, VALIDATED

Fields inherited from class gnu.mapping.Procedure

applyMethodType, applyToConsumerDefault, applyToConsumerMethod, applyToObjectDefault, applyToObjectMethod, compilerKey, compilerXKey, inlineIfConstantSymbol, validateApplyKey, validateXApplyKey

Fields inherited from class gnu.mapping.PropertySet

nameKey

Constructor Summary

Constructors

Constructor	Description
CaseExp(Expression key, CaseExp.CaseClause[] clauses)	Constructor for a case expression with no else clause.
CaseExp(Expression key, CaseExp.CaseClause[] clauses, CaseExp.CaseClause elseClause)	Constructor for a case expression with an else clause.

Method Summary

Modifier and Type	Method	Description
void	apply(CallContext ctx)	Evaluate the expression.
protected Type	calculateDatumsType()	Computes the union type of the case expression datums.
protected Object	calculateDatumValue(Expression datum)	Given the expression generated from a datum returns the value of the datum as an Object.
protected Type	calculateType()
void	compile(Compilation comp, Target target)
protected boolean	mustCompile()
void	print(gnu.kawa.io.OutPort out)
boolean	searchValue(Object keyValue)	Search a clause containing the specified key.
Expression	selectCase(Object keyValue)	Search for a clause containing the specified key.
protected <R, D> R	visit(ExpVisitor<R,D> visitor, D d)
protected <R, D> void	visitChildren(ExpVisitor<R,D> visitor, D d)

Methods inherited from class gnu.expr.Expression

applyMethodExpression, checkLiteralKeyword, compile, compile, compileWithPosition, compileWithPosition, deepCopy, deepCopy, deepCopy, deepCopy, eval, eval, getColumnNumber, getEndColumn, getEndLine, getFileName, getFlag, getFlags, getLineNumber, getPublicId, getStartColumn, getStartLine, getSystemId, getType, getTypeRaw, isSingleValue, isStableSourceLocation, makeWhile, maybeSetLine, neverReturns, numArgs, print, printLineColumn, setFile, setFlag, setFlag, setLine, setLine, setLine, setLine, setLine, setLocation, setType, side_effects, toString, validateApply, valueIfConstant

Methods inherited from class gnu.mapping.Procedure

apply0, apply1, apply2, apply3, apply4, applyL, applyN, applyToConsumerDefault, applyToObjectDefault, checkArgCount, checkBadCode, getApplyMethod, getApplyToConsumerMethod, getApplyToObjectMethod, getReturnType, getSetter, getSourceLocation, isSideEffectFree, lookupApplyHandle, maxArgs, maxArgs, minArgs, minArgs, set0, set1, setN, setSetter, setSourceLocation

Methods inherited from class gnu.mapping.PropertySet

getName, getProperty, getSymbol, removeProperty, setName, setProperty, setProperty, setSymbol

Methods inherited from class java.lang.Object

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

Constructor Details

CaseExp

public CaseExp(Expression key,
 CaseExp.CaseClause[] clauses)

Constructor for a case expression with no else clause. Arguments must be non null. clauses parameter must contain at least one CaseClause.

CaseExp

public CaseExp(Expression key,
 CaseExp.CaseClause[] clauses,
 CaseExp.CaseClause elseClause)

Constructor for a case expression with an else clause. Arguments must be non null.

Method Details

mustCompile

protected boolean mustCompile()

Specified by:

mustCompile in class Expression

apply

public void apply(CallContext ctx)
           throws Throwable

Description copied from class: Expression

Evaluate the expression. This is named apply rather than eval so it is compatible with the full-tail-call calling convention, and we can stash an Expression in CallContext's proc field. FIXME - are we making use of this?

Overrides:

apply in class Expression

Throws:

Throwable

print

public void print(gnu.kawa.io.OutPort out)

Specified by:

print in class Expression

compile

public void compile(Compilation comp,
 Target target)

Specified by:

compile in class Expression

visit

protected <R,
D> R visit(ExpVisitor<R,D> visitor,
 D d)

Overrides:

visit in class Expression

visitChildren

protected <R,
D> void visitChildren(ExpVisitor<R,D> visitor,
 D d)

Overrides:

visitChildren in class Expression

calculateDatumValue

protected Object calculateDatumValue(Expression datum)

Given the expression generated from a datum returns the value of the datum as an Object.

calculateType

protected Type calculateType()

Overrides:

calculateType in class Expression

calculateDatumsType

protected Type calculateDatumsType()

Computes the union type of the case expression datums. Useful to know if the datums are all integer values.

searchValue

public boolean searchValue(Object keyValue)

Search a clause containing the specified key. If the clause is found returns true, false otherwise.

selectCase

public Expression selectCase(Object keyValue)

Search for a clause containing the specified key. If the clause is found returns the corresponding expression.