org.erights.e.elang.evm
Class FinallyExpr

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.FinallyExpr

All Implemented Interfaces:

Cloneable, EPrintable, MatchMaker

public class FinallyExpr

extends EExpr

Safe: BNF: "try" block "finally" block

Evaluates the try-clause, but exiting to the enclosing context also evaluate the finally-clause. If the finally-clause exits normally (evaluates to a value), then the exit of the FinallyExpr as a whole is the exit of the try-clause. In other words, if the try-clause evaluates to a value, then the FinallyExpr evaluates to that same value. If the try-clause throws or escapes, then the FinallyExpr as a whole likewise throws or escapes.

On the other hand, if the finally-clause does a non-local exit (throws or escapes) then the FinallyExpr as a whole exits in that way. A non-local finally-clause exit replaces the try-clause exit as the means of exiting.

Author:

Mark S. Miller

Field Summary

private EExpr	myAttempt
private EExpr	myUnwinder

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

FinallyExpr(SourceSpan optSpan, EExpr attempt, EExpr unwinder)
Enabled:

Method Summary

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

myAttempt

private final EExpr myAttempt

myUnwinder

private final EExpr myUnwinder

Constructor Detail

FinallyExpr

public FinallyExpr(SourceSpan optSpan,
                   EExpr attempt,
                   EExpr unwinder)

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

matchBind

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

Enabled:

Specified by:

matchBind in interface MatchMaker

Specified by:

matchBind in class ParseNode

attempt

public EExpr attempt()

Enabled:

unwinder

public EExpr unwinder()

Enabled:

subPrintOn

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

Enabled:

Specified by:

subPrintOn in class ParseNode

IOException