The #compilerClass method allows you to specify the compiler to be  
used for a class (and its subclasses).  So, one approach would be to  
implement a subclass of Compiler (say, "ProxyCompiler") that disables  
optimization of #ifTrue:ifFalse: etc.

I'm not sure about a clean way to disable optimizations in a subclass  
of Compiler.  Here's a moderately horrible way to disable them  
globally...
	- give Compiler a boolean class variable "DisableSpecialSelectors"
	- hack MethodNode>>noteSpecialSelector: thusly...

noteSpecialSelector: selectorSymbol
	" special > 0 denotes specially treated messages. "

	DisableSpecialSelectors ifTrue: [special := 0. ^self].

	"Deconvert initial keywords from SQ2K"
	special := #(:Test:Yes: :Test:No: :Test:Yes:No: :Test:No:Yes:
				and: or:
				:Until:do: :While:do: whileFalse whileTrue
				:Repeat:to:do: :Repeat:to:by:do:
				) indexOf: selectorSymbol.
	special > 0 ifTrue: [^ self].

	special := MacroSelectors indexOf: selectorSymbol.


Then, you could override #translate:noPattern:ifFail: in  
ProxyCompiler, as follows...

translate: aStream noPattern: noPattern ifFail: failBlock
	[	DisableSpecialSelectors := true.
		^super translate: aStream noPattern: noPattern ifFail: failBlock
	] ensure: [DisableSpecialSelectors := false].


Finally, implement #compilerClass on the class-side of your Proxy  
class, and answer ProxyCompiler.	

Heh, that was sorta fun!
Josh




On Mar 4, 2008, at 10:39 PM, Igor Stasenko wrote:

> On 05/03/2008, Paolo Bonzini <bonzini at gnu.org> wrote:
>> Igor Stasenko wrote:
>>> Hello,
>>>
>>> i currently tried to implement a proxy (subclass of ProtoObject)  
>>> with
>>> own IfTrue:/ifFalse: methods.
>>> What i can't understand, is why VM throws me with #mustBeBoolean
>>> message instead of doing real send if optimized pattern fails (when
>>> receiver of #IfTrue: is a non-boolean)?
>>
>>
>> Because you cannot distinguish #ifTrue:#ifFalse: sends from  
>> #whileTrue:
>> for example, and because there are no BlockC{ontext,losure} objects  
>> for
>> the argument blocks.
>>
>
> So, the only way is to compile method without optimization of  
> #ifTrue #ifFalse:,
> to make sure they do real sends?
>
> If yes, i'd like to see optimizations optional, so people can do like:
>
> Compiler turnOffOptimizations.
> MyClass compileAll.
> Compiler turnOnOptimizations.
>
>>
>> Paolo
>>
>>
>
>
> -- 
> Best regards,
> Igor Stasenko AKA sig.
>