nicolas cellier a écrit :
> Le Jeudi 20 Juillet 2006 00:38, mathieu a écrit :
>> Hi,
>>
>> It is normal that:
>>
>> (DependentsArray new: 100) size
>>
>> return 0?
> 
> Yes
> 
>> If yes so why?
> 
> DependentsArray count only non nil elements
> 
>> And if I do:
>> | o |
>>
>> o := WriteStream on: (DependentsArray new: 100).
>> 1 to: 24 do: [:each | o nextPut: Object new]. "do it sevral time"
>>
>> it raise an error 'subscript is out of bounds: 22' from time to time
>> why?
> 
> You cannot do that with DependentsArray.
> 
> DependentsArray are weak array: that mean that storing an object into a
> DependentsArray does not prevent it from being garbageCollected.
> 
> When an element is garbage collected, corresponding index in DependentsArray
> is replaced by nil.
> 
> All is occuring in pastEndPut:
> Since initial size (non nil elements) is zero, then the array is grown to 
> size: oldSize + ((oldSize max: 20) min: 1000000)
> 
> When no garbageCollection occurs, that works fine (except a new
> DependentsArray is created each time you add an Object).
> 
> When a garbage collect occurs, all unreferenced (Object new) are removed from
> the DependentsArray, except one (I do not know who is referencing it, maybe
> the BlockContext...).
> 
> Thus you allocate a DependentsArray of size 21 and fail when storing element
> number 22...
> 
>> Thx
>> Math
> 
> What do you need DependentsArray for?
> 
> Nicolas

ok thx :)

In fact this is "used" in SmaCC and raise this error:

======================================================
DependentsArray(Object)>>error:
	Receiver: a DependentsArray(<keyword> ")" "]" <binarySymbol> "}" ";"
<period> ">" <name> E O F)
	Arguments and temporary variables:
		aString: 	*'subscript is out of bounds: 23'*
	Receiver's instance variables:
a DependentsArray(<keyword> ")" "]" <binarySymbol> "}" ";" <period> ">"
<name> E O F)

DependentsArray(Object)>>errorSubscriptBounds:
	Receiver: a DependentsArray(<keyword> ")" "]" <binarySymbol> "}" ";"
<period> ">" <name> E O F)
	Arguments and temporary variables:
		index: 	23
	Receiver's instance variables:
a DependentsArray(<keyword> ")" "]" <binarySymbol> "}" ";" <period> ">"
<name> E O F)

DependentsArray(Object)>>at:put:
	Receiver: a DependentsArray(<keyword> ")" "]" <binarySymbol> "}" ";"
<period> ">" <name> E O F)
	Arguments and temporary variables:
		index: 	23
		value: 	
	Receiver's instance variables:
a DependentsArray(<keyword> ")" "]" <binarySymbol> "}" ";" <period> ">"
<name> E O F)

WriteStream>>pastEndPut:
	Receiver: <<error during printing>>
	Arguments and temporary variables:
		anObject: 	
		oldSize: 	2
		grownCollection: 	a DependentsArray(<keyword> ")" "]" <binarySymbol>
"}" ";" <pe...etc...
	Receiver's instance variables:
		collection: 	a DependentsArray(<keyword> ")" "]" <binarySymbol> "}"
";" <period>...etc...
		position: 	23
		readLimit: 	23
		writeLimit: 	1


--- The full stack ---
DependentsArray(Object)>>error:
DependentsArray(Object)>>errorSubscriptBounds:
DependentsArray(Object)>>at:put:
WriteStream>>pastEndPut:
 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
WriteStream>>nextPut:
[] in DependentsArray>>copyWith: {[:s |  self   do: [:item | s nextPut:
item].  s nextPut: newElement]}
DependentsArray class(SequenceableCollection class)>>streamContents:
DependentsArray>>copyWith:
DependentsArray(Array)>>copyWithDependent:
SmaCCSymbolSet(Object)>>addDependent:
SmaCCSymbolSet>>addComponent:
SmaCCSymbolSet>>baseOn:
SmaCCSymbolSet class>>basedOn:
SmaCCLR1Item>>moveNext
[] in SmaCCItemSet>>moveOn: {[:each | each nextSymbol == aGrammarSymbol
  ifTrue: [anItemSet add: each mo...]}
SmaCCItemSet(Set)>>do:
SmaCCItemSet>>moveOn:
[] in SmaCCGrammarCompiler>>createItemSets {[:each |  newState :=
itemSet moveOn: each.  newState notEmpty   ifTrue: [sh...]}
SortedCollection(OrderedCollection)>>do:
SmaCCGrammarCompiler>>createItemSets
SmaCCGrammarCompiler>>transitionTable
SmaCCGrammarCompiler>>compileTransitionTable
SmaCCGrammarCompiler>>compileParser
SmaCCGrammarCompiler>>createChanges
======================================================