edu.vub.at.objects.natives
Class NATClosure

java.lang.Object
  edu.vub.at.objects.natives.NATNil
      edu.vub.at.objects.natives.NATByRef
          edu.vub.at.objects.natives.NATClosure

All Implemented Interfaces:

ATAbstractGrammar, ATClosure, ATConversions, ATExpression, ATNil, ATObject, ATStatement, java.io.Serializable

Direct Known Subclasses:

JavaClosure, NativeClosure

public class NATClosure

extends NATByRef

implements ATClosure

A NATClosure instance represents a first-class AmbientTalk closure. A closure is modelled as a pair (method, context), where the method contains the pure function (function name, arguments and body). The single most important operation to be performed on a closure is applying it. This will give rise to the application of its underlying method within the context wrapped by the closure.

Author:

smostinc

See Also:

Serialized Form

Nested Class Summary

private static class

NATClosure.QuitClosureFrame

Field Summary

protected ATContext	context_
protected ATMethod	method_

Fields inherited from class edu.vub.at.objects.natives.NATNil

_INSTANCE_

Constructor Summary

NATClosure(ATMethod method, ATContext context)

NATClosure(ATMethod method, ATObject implementor, ATObject receiver)
This constructor creates a closure with a bound dynamic receiver, and it is called after the succesful lookup of a receiverful message.

Method Summary

ATObject	base_apply(ATTable arguments) To apply a closure, apply its underlying method with the context of the closure, rather than the runtime context of the invoker.
ATObject	base_applyInScope(ATTable args, ATObject scope) To apply a closure in a given scope, apply its underlying method with a new context constructed from the scope object.
ATClosure	base_asClosure()
ATObject	base_escape() The following is a pseudo-code implementation of escape.
ATContext	base_getContext() Structural access to the scope of the closure.
ATMethod	base_getMethod() Structural access to the encapsulated method.
boolean	base_isClosure()
ATObject	base_whileTrue_(ATClosure body) receiver is a zero-argument block closure returning a boolean
ATTable	meta_getStripes() Returns the stripes of this object.
NATText	meta_print() Prints out the object in a human-readable way.

Methods inherited from class edu.vub.at.objects.natives.NATByRef

meta_pass, meta_resolve

Methods inherited from class edu.vub.at.objects.natives.NATNil

asAmbientTalkObject, asJavaClassUnderSymbiosis, asJavaObjectUnderSymbiosis, asNativeBoolean, asNativeException, asNativeFarReference, asNativeFraction, asNativeNumber, asNativeNumeric, asNativeTable, asNativeText, base__opeql__opeql_, base_asActorMirror, base_asAsyncMessage, base_asBegin, base_asBoolean, base_asDefinition, base_asExpression, base_asFarReference, base_asField, base_asHandler, base_asMessage, base_asMessageCreation, base_asMethod, base_asMirror, base_asNumber, base_asSplice, base_asStatement, base_asStripe, base_asSymbol, base_asTable, base_asUnquoteSplice, base_asVariableAssignment, base_init, base_isBoolean, base_isCallFrame, base_isFarReference, base_isMessageCreation, base_isMethod, base_isMirror, base_isSplice, base_isStripe, base_isSymbol, base_isTable, base_isUnquoteSplice, base_isVariableAssignment, base_new, createChild, equals, isAmbientTalkObject, isJavaObjectUnderSymbiosis, isNativeBoolean, isNativeField, isNativeText, meta_addField, meta_addMethod, meta_assignField, meta_assignVariable, meta_clone, meta_defineField, meta_doesNotUnderstand, meta_eval, meta_extend, meta_getDynamicParent, meta_getLexicalParent, meta_grabField, meta_grabMethod, meta_invoke, meta_isCloneOf, meta_isRelatedTo, meta_isStripedWith, meta_listFields, meta_listMethods, meta_lookup, meta_newInstance, meta_quote, meta_receive, meta_respondsTo, meta_select, meta_send, meta_share, readResolve, toString, writeReplace

Methods inherited from class java.lang.Object

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

Methods inherited from interface edu.vub.at.objects.ATObject

base__opeql__opeql_, base_init, base_new, meta_addField, meta_addMethod, meta_assignField, meta_assignVariable, meta_clone, meta_defineField, meta_doesNotUnderstand, meta_eval, meta_extend, meta_getDynamicParent, meta_getLexicalParent, meta_grabField, meta_grabMethod, meta_invoke, meta_isCloneOf, meta_isRelatedTo, meta_isStripedWith, meta_listFields, meta_listMethods, meta_lookup, meta_newInstance, meta_pass, meta_quote, meta_receive, meta_resolve, meta_respondsTo, meta_select, meta_send, meta_share

Methods inherited from interface edu.vub.at.objects.coercion.ATConversions

asAmbientTalkObject, asJavaClassUnderSymbiosis, asJavaObjectUnderSymbiosis, asNativeBoolean, asNativeException, asNativeFarReference, asNativeFraction, asNativeNumber, asNativeNumeric, asNativeTable, asNativeText, base_asActorMirror, base_asAsyncMessage, base_asBegin, base_asBoolean, base_asDefinition, base_asExpression, base_asFarReference, base_asField, base_asHandler, base_asMessage, base_asMessageCreation, base_asMethod, base_asMirror, base_asNumber, base_asSplice, base_asStatement, base_asStripe, base_asSymbol, base_asTable, base_asUnquoteSplice, base_asVariableAssignment, base_isBoolean, base_isCallFrame, base_isFarReference, base_isMessageCreation, base_isMethod, base_isMirror, base_isSplice, base_isStripe, base_isSymbol, base_isTable, base_isUnquoteSplice, base_isVariableAssignment, isAmbientTalkObject, isJavaObjectUnderSymbiosis, isNativeBoolean, isNativeField, isNativeText

Field Detail

method_

protected ATMethod method_

context_

protected ATContext context_

Constructor Detail

NATClosure

public NATClosure(ATMethod method,
                  ATObject implementor,
                  ATObject receiver)
           throws InterpreterException

This constructor creates a closure with a bound dynamic receiver, and it is called after the succesful lookup of a receiverful message.

Parameters:

method - the method being wrapped into a closure.

implementor - the object in which the definition is nested.

receiver - the object where the lookup was initiated.

NATClosure

public NATClosure(ATMethod method,
                  ATContext context)

Method Detail

base_apply

public ATObject base_apply(ATTable arguments)
                    throws InterpreterException

To apply a closure, apply its underlying method with the context of the closure, rather than the runtime context of the invoker.

Specified by:

base_apply in interface ATClosure

Parameters:

arguments - the already evaluated arguments, wrapped in a table

Returns:

the value of evaluating the method body in the context of the closure

Throws:

InterpreterException

base_applyInScope

public ATObject base_applyInScope(ATTable args,
                                  ATObject scope)
                           throws InterpreterException

To apply a closure in a given scope, apply its underlying method with a new context constructed from the scope object.

Specified by:

base_applyInScope in interface ATClosure

Parameters:

args - the already evaluated arguments, wrapped in a table

scope - the object that will act as self and as lexically enclosing scope.

Returns:

the value of evaluating the method body in the context of the given object scope

Throws:

InterpreterException

base_whileTrue_

public ATObject base_whileTrue_(ATClosure body)
                         throws InterpreterException

receiver is a zero-argument block closure returning a boolean

Specified by:

base_whileTrue_ in interface ATClosure

Parameters:

body - a zero-argument block closure def whileTrue: body { self.apply().ifTrue: { body(); self.whileTrue: body } }

Throws:

InterpreterException

base_escape

public ATObject base_escape()
                     throws InterpreterException

The following is a pseudo-code implementation of escape. The important difference between the native implementation and this pseudo-code is that the 'escaping exception' can *not* be caught at the AmbientTalk level. The SignalEscape is a truly native exception. def block.escape() { def returned := false; def quit(@args) { if: (returned) then: { raise: XIllegalOperation.new("Cannot quit, escape activation already returned") } else: { raise: SignalEscape.new(block, if: (args.isEmpty()) then: nil else: args[1]) } }; try: { block(quit); } catch: SignalEscape using: {|e| if: (e.block == block) then: { e.val } else: { raise: e } } finally: { // doesn't yet exist in AT/2 returned := true; } }

Specified by:

base_escape in interface ATClosure

Throws:

InterpreterException

base_getContext

public ATContext base_getContext()
                          throws InterpreterException

Description copied from interface: ATClosure

Structural access to the scope of the closure.

Specified by:

base_getContext in interface ATClosure

Throws:

InterpreterException

base_getMethod

public ATMethod base_getMethod()

Description copied from interface: ATClosure

Structural access to the encapsulated method.

Specified by:

base_getMethod in interface ATClosure

base_isClosure

public boolean base_isClosure()

Specified by:

base_isClosure in interface ATConversions

Overrides:

base_isClosure in class NATNil

base_asClosure

public ATClosure base_asClosure()

Specified by:

base_asClosure in interface ATConversions

Overrides:

base_asClosure in class NATNil

meta_print

public NATText meta_print()
                   throws InterpreterException

Description copied from interface: ATObject

Prints out the object in a human-readable way.

Specified by:

meta_print in interface ATObject

Overrides:

meta_print in class NATNil

Throws:

InterpreterException

meta_getStripes

public ATTable meta_getStripes()
                        throws InterpreterException

Description copied from interface: ATObject

Returns the stripes of this object. Note that only the stripes that were attached directly to this object are returned, not all of the parent's stripes as well.

Specified by:

meta_getStripes in interface ATObject

Overrides:

meta_getStripes in class NATNil

Throws:

InterpreterException