org.erights.e.elang.evm
Class EscapeExpr

java.lang.Object
  |
  +--org.erights.e.elang.evm.ParseNode
        |
        +--org.erights.e.elang.evm.ENode
              |
              +--org.erights.e.elang.evm.EExpr
                    |
                    +--org.erights.e.elang.evm.EscapeExpr

All Implemented Interfaces:

Cloneable, EPrintable, MatchMaker

public class EscapeExpr

extends EExpr

Safe: BNF: "escape" pattern "{" expr "}"

Evaluates 'expr' in an environment where 'pattern' is bound to an Ejector. If the Ejector is never called, expr evalutes normally. If Ejector is called during the execution of the expr, the expr exits, evaluating to Ejector's argument.

On the way out, any 'finally' clauses are run.

Author:

Mark S. Miller

See Also:

org.erights.e.elang.evm.CatchExpr, org.erights.e.elang.evm.FinallyExpr

Field Summary

private Pattern	myExitPatt
private EExpr	myRValue

Fields inherited from class org.erights.e.elang.evm.ENode

Fields inherited from class org.erights.e.elang.evm.ParseNode

NUM_PR, PR_ASSIGN, PR_CALL, PR_COMP, PR_EEXPR, PR_LISTPATT, PR_ORDER, PR_PATTERN, PR_PRIM, PR_START

Constructor Summary

EscapeExpr(SourceSpan optSpan, Pattern exitPatt, EExpr rValue)
Enabled:

Method Summary

protected StaticScope	computeStaticScope() When staticScope() is first requested on a given node, it calls computeStaticScope() to do the actual computation, which is then remembered.
Pattern	exitPattern() Enabled:
boolean	matchBind(ConstList args, Object specimen, FlexList bindings) Enabled:
EExpr	rValue() Enabled:
protected Object	subEval(EvalContext ctx, boolean forValue) The recursive part that does the work
void	subPrintOn(TextWriter out, int priority) Enabled:
Object	welcome(ETreeVisitor visitor) Enabled:

Methods inherited from class org.erights.e.elang.evm.EExpr

__printOn, appendAllTo, appendTo, eval, eval, evalBool, printAsBlockOn, substitute, transform

Methods inherited from class org.erights.e.elang.evm.ENode

cleanCopy, copy, getOptPatternMap, getOptScopeMap, getPatternMap, getScopeMap, qbuild, setPatternMap, setScopeMap, staticScope, synEnv

Methods inherited from class org.erights.e.elang.evm.ParseNode

asText, getOptSpan, lnPrintOn, lnPrintOn, matchBind, matchBind, matchBind, printListOn, toString

Methods inherited from class java.lang.Object

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

Field Detail

myExitPatt

private final Pattern myExitPatt

myRValue

private final EExpr myRValue

Constructor Detail

EscapeExpr

public EscapeExpr(SourceSpan optSpan,
                  Pattern exitPatt,
                  EExpr rValue)

Enabled:

Method Detail

welcome

public Object welcome(ETreeVisitor visitor)

Enabled:

Specified by:

welcome in class ENode

computeStaticScope

protected StaticScope computeStaticScope()

Description copied from class: ENode

When staticScope() is first requested on a given node, it calls computeStaticScope() to do the actual computation, which is then remembered.

Specified by:

computeStaticScope in class ENode

subEval

protected Object subEval(EvalContext ctx,
                         boolean forValue)

Description copied from class: EExpr

The recursive part that does the work

Specified by:

subEval in class EExpr

exitPattern

public Pattern exitPattern()

Enabled:

matchBind

public boolean matchBind(ConstList args,
                         Object specimen,
                         FlexList bindings)

Enabled:

Specified by:

matchBind in interface MatchMaker

Specified by:

matchBind in class ParseNode

subPrintOn

public void subPrintOn(TextWriter out,
                       int priority)
                throws IOException

Enabled:

Specified by:

subPrintOn in class ParseNode

IOException

rValue

public EExpr rValue()

Enabled: