[Vm-dev] squeak decompiler
whiter.walt at gmail.com
Mon Oct 20 12:59:50 UTC 2014
thanks for your reply!
do you know for sure, there is information about decompiling in one of
these books? Because I could not find anything!
Am 20.10.2014 13:13, schrieb karl ramberg:
> Free books here:
> Early Squeak was pretty similar to the description in
> On Mon, Oct 20, 2014 at 12:01 PM, Casey Ransberger
> <casey.obrien.r at gmail.com <mailto:casey.obrien.r at gmail.com>> wrote:
> I don't know anything about how the Squeak decompiler works.
> One approach to translating code in one language to another is to
> build a parser for the source language in order to obtain an
> abstract syntax tree (AST) and then use a pretty-printer for the
> target language on the AST. That's the short, short version of an
> explanation of how we translate the Squeak VM from Slang to C.
> In the case of a decompiler for a byte compiled system, the source
> language (using the above approach) would be the bytecodes
> themselves, and the target language could be any language with
> sufficient facilities to support the semantics of the source
> language (in the case of a decompiler, the target language would
> be the original language used to compile the e.g. bytecode.)
> I hesitated to respond, because I definitely don't know anything
> about Squeak's decompiler, and also because what I've described is
> in some ways a massive oversimplification (if the compiler is
> optimizing things, deoptimization may be necessary to approach the
> intent and style of the original programmer's code, and that's
> just one thing I can think of.)
> We have available to us a couple of tools which make it
> (relatively) easy to play around with this idea and get a feel for
> it (OMeta/Squeak and PetitParser.)
> I'd recommend checking out PetitParser if you're messing with
> stuff to do with compilation, as OMeta's development seems to
> Decompilation hasn't been an area of interest for me, and I don't
> know much about it, so I may be sending you down the primrose
> path. In the immortal words of LeVar Burton, "don't take my word
> for it."
> I know that several research papers have been written about OMeta,
> and I'd bet some have been written about PetitParser as well. The
> focus of these systems is on parsing expression grammars (PEGs,)
> but language to language translation is a thing, and it seems to
> me that a decompiler can be viewed as a special case of this
> thing. Following the references cited in such papers could prove
> valuable to whatever your cause is.
> For historical perspective on OMeta and PetitParser, it might be
> helpful looking into the meta language called Meta-2.
> Arguably, this question would be as well addressed on squeak-dev,
> as both the compiler and the decompiler are image-residents, and
> not built into the VM (though both are tied to the VM's behavior
> wrt interpreting bytecode.)
> HTH, sorry if it doesn't.
> People who actually know how Squeak's decompiler works should
> still probably chime in here :D
> > On Oct 20, 2014, at 1:51 AM, Whiter Walt <whiter.walt at gmail.com
> <mailto:whiter.walt at gmail.com>> wrote:
> > Hi,
> > I am interested in the Squeak Decompiler class. Is there any
> technical information in the net, which explains the
> functionality? Or maybe it follows some common "rules", I can find
> in some paper or book?
> > cheers
> > Walt
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