Eliot Miranda wrote:
>
>
> On Fri, Dec 2, 2011 at 5:13 PM, Eliot Miranda <eliot.miranda at gmail.com 
> <mailto:eliot.miranda at gmail.com>> wrote:
>
>
>
>     On Fri, Dec 2, 2011 at 4:01 PM, Juan Vuletich <juan at jvuletich.org
>     <mailto:juan at jvuletich.org>> wrote:
>
>         Eliot Miranda wrote:
>
>             Hi Juan,
>
>             ...
>
>
>
>                I can say that it does indeed work. But I'd be really
>             grateful if
>                Eliot took a good look at that code!
>
>
>             There is a much better way, using
>             InstructionStream>>interpreetNextInstructionFor: which
>             abstracts away from the bytecode encoding and allows one
>             to simply use messages.  e.g. look at
>
>             and (SortedCollection sortBlock: [:a :b| a compare: b
>             caseSensitive: false]) sortBlock abstractBytecodes
>             evaluates to
>
>             an OrderedCollection(#pushTemporaryVariable:
>             #pushTemporaryVariable: #pushConstant: #send:super:numArgs:)
>
>             So a check for clean blocks would check for a block's
>             abstractBytecodes not including some particular set of
>             banned messages (which I *think* is pushReceiver
>             pushReceiverVariable: popIntoReceiverVariable:
>             storeIntoReceiverVariable: methodReturnConstant:
>             methodReturnReceiver methodReturnTop).
>
>             e.g.
>
>             isClean
>                  ^(self abstractBytecodes intersection: #(pushReceiver
>             pushReceiverVariable: popIntoReceiverVariable:
>             storeIntoReceiverVariable: methodReturnConstant:
>             methodReturnReceiver methodReturnTop)) isEmpty
>
>
>                Cheers,
>                Juan Vuletich
>
>
>
>
>             -- 
>             best,
>             Eliot
>
>
>         Thanks Eliot. However, it looks to me that this needs more
>         tweaking. 
>
>
>     <blush>Damn right :)  I've done zero testing.  It was just an
>     example</blush>
>      
>
>         For instance, your method answers true for
>           [ xx size ] isClean
>         and
>           [ ^ nil ] isClean
>         while mine answers false for both. Maybe we could serialize
>         non local returns using the Compiler (although we won't be
>         able to return anywhere), but external variable acess is a
>         problem.
>
>         Will keep playing with this for a while...
>
>
>     Can you (can I??) write some tests?  What's xx in the above?  Ah!
>     [^nil] isn't clean in my code since it should be pc <= end, not pc
>     < end!!  Try the attached...
>
>
> having played around with this some it strikes me we might want a 
> method that checks whether a block refers only to block local 
> variables and constants, or block locals, globals and constants.  Say 
> BlockClosure>>isSqueakyClean ;)

Right. That's what my version of #isClean wants.

>
>      
>
>
>         Cheers,
>         Juan Vuletich
>
>
>
>
>     -- 
>     best,
>     Eliot
>
>
>
>
> -- 
> best,
> Eliot
>


Cheers,
Juan Vuletich