[Newbies] How to know where a BlockClosure finish

[Mathieu]

Ron Teitelbaum a écrit :
> Hi Math, 
> 
> How about just adding a parameter?
> 
> Blocks are really cool in that they can import context if needed.  This is a
> really amazing feature of blocks for me since the imported context is the
> context when the block was created!
> 
> So to solve your problem you could just do the following.
> 
> continue := true.
> 
> block1 := [someCode.
> 		someCondition ifTrue: [continue := false. ^someValue]].
> block2 := [someCode].
> 
> Then:
> 
> block1 value.
> continue ifTrue: [
>     block2 value
> ].
> 
> Hope that helps!
> 
> Happy coding.

Thanks Ron but in fact it's in a context that we don't know where are
the return and we also don't know how many "block" we have. :)


> 
> Ron Teitelbaum
> President / Principal Software Engineer
> US Medical Record Specialists
> Ron at USMedRec.com 
> 
>> From: Mathieu
>> Sent: Friday, August 25, 2006 1:10 PM
>>
>> Marcus Denker a écrit :
>>> On 25.08.2006, at 17:14, Mathieu wrote:
>>>
>>>> Hi,
>>>>
>>>> I want to execute several block:
>>>>
>>>> block1 value
>>>> block2 value
>>>> block3 value
>>>>
>>>> but if one block return from a retrun statement I want to quit.
>>>>
>>>> [^3] <- want to quit here
>>>> [3 + 4]
>>>>
>>>> So is there a way to know when a block evaluation finish by a return?
>>>>
>>> There is #hasMethodReturn in BlockContext:
>>>
>>> [^3] hasMethodReturn --> true
>>> [3] hasMethodReturn --> false.
>>>
>>> But this does a static analysis of the code... even if the ^is not
>> executed
>>> (e.g.)
>>> [nil ifNotNil: [^3]]  hasMethodReturn --> true
>>>
>>> so... it would be harder to analyze that dynamically... e.g. (without
>>> me  thinking
>>> to much) you could add code (e.g. using ByteSurgeon)
>>> in front of the return inside a block to set a flag... but I have to
>>> admit that this
>>> woud be quite strange stuff...
>>>
>>>> I need this to interprete a file containing smalltalk and I want to
>>>> control the execution beceause I need to add some condition befor
>>>> evaluate a block.
>>> Why do you need that? I am sure we can find a simple solution if we
>>> understand
>>> the problem better.
>>>
>>>    Marcus
>>>
>>>
>> Yes you are right
>>
>> In the script I have 2 kind of things:
>> [
>> some Smalltalk
>> ]
>>
>> And:
>>
>> Class selector
>> [
>> some smalltalk
>> ]
>>
>> So my idea was to call Compiler>>#evaluate:in:to:notifying:ifFail:logged:
>> on the string inside the [] for the first things.
>>
>> And for the second I don't know yet but I don't think it's a probleme.
>>
>> So I evaluate the "block" one by one. I don't think I can put them all
>> together beceause we can declare new method and use it in the next
>> "block".
>>
>> But may be I shouln't evaluate right now juste store them in a
>> CompiledMethod...
>>
>> Math
>>