On Mon, Mar 2, 2009 at 3:25 PM, Igor Stasenko <siguctua at gmail.com> wrote:

> 2009/3/3 Eliot Miranda <eliot.miranda at gmail.com>:
> - Show quoted text -
> >
> >
> > On Mon, Mar 2, 2009 at 1:48 PM, Stephen Pair <stephen at pairhome.net>
> wrote:
> >>
> >> On Mon, Mar 2, 2009 at 12:38 AM, Eliot Miranda <eliot.miranda at gmail.com
> >
> >> wrote:
> >>>
> >>>
> >>> On Sun, Mar 1, 2009 at 9:20 PM, Craig Latta <craig at netjam.org> wrote:
> >>>>
> >>>> [snip]
> >>>>     As for whether to produce an object memory statically and then set
> >>>> it running, or transform an object memory which is always running... I
> think
> >>>> the resulting memory will need to load modules live anyway, so one
> might as
> >>>> well do all the transformations that way. Perhaps this is simply an
> >>>> aesthetic choice.
> >>>
> >>> Surely repeatability mandates that one roduce an object memory
> statically
> >>> and then set it running?  Because of things like delays the always
> running
> >>> memory is almost never in a predictable state, so one always ends up
> with
> >>> different bits even if they represent the same functionality.
> >>> E.
> >>
> >> Maybe you could get the repeatability with a process that is roughly:
> >> a) write the spec for the capability of the image (a method that
> exercises
> >> everything you want to be able to do)
> >> b) use the class/method copying & DNU trickery and do the runtime
> analysis
> >> to figure out the classes and methods needed to support that capability
> >> c) do something a little more surgical to build a new image by copying
> >> over the behaviors and methods, but construct the processes and stacks
> more
> >> deliberately (so you aren't so tied to the running image's state)
> >> I'd think in this way you could do something that was reproducible to
> the
> >> extent that resulting image was only dependent on the running image for
> its
> >> behaviors and other necessary objects (various singletons and whatnot),
> but
> >> otherwise not affected by various processes and random other things that
> >> might be in that image.  Once you had (b) and (c) mostly ironed out, it
> >> would be a process of refining the specification in (a) to get to a
> suitable
> >> minimal image.
> >
> > Agreed.  The nice thing is being able to run a) in the IDE so that when
> > something is missing it manifests as an Undeclared or an MNU.
> > One thing is ensuring that when simulating objects like nil, true and
> false
> > behave as they will in the result, not as defined in the host image.  One
> > thing one could do is arrange that the compiler for MObject uses
> instances
> > of MSymbol for all code under MObject.  Then e.g. a doesNotUnderstand:
> > handler on SmallInteger, UndefinedObject, Boolean et al might be able to
> > forward things correctly and arrange that the simulation was more
> accurate.
> >
>
> Thats why i wrote own parser/compiler in Moebius.
> It is designed in a way, that a parser & compiler output is under full
> control of an object which plays role as environment.
> So, you can produce an instance of CompiledMethod as output, or encode
> result in machine code, or represent methods as a raw bytes which then
> could be put in the image you constructing.
> Even nil,true,false singleton values are under control of environment.
>
> Read more about it here.
> http://code.google.com/p/moebius-st/wiki/Parser
>
> Simulation of SmallInts could be made easy - we could simply make a
> class, named BoxedSmallInteger
> and use it for representing all literal values in methods. At final
> stage of image creating we can unbox them and replace by smallints.


Cool.  So the compiler can avoid using the pushNil, pushFalse and pushTrue
bytecodes.  It must send some message to coerce every MBoolean result into a
host Boolean before doing a conditional jump.  It must wrap all
MSmallInteger relational primitive invocations with code to coerce the
Booleran to the matching MBoolean.

A doesNotUnderstand: will produce an instance of Message and send
doesNotUnderstand:, do MObject needs a doesNtUnderstand: handler that sends
MSymbol #doesNotUnderstand: with a coercion of the Message to an MMessage.
 Any other holes that need to be plugged?

Alternatively just create a subclass of InstructionStream and/or ContextPart
and interpret all code and have the interpretation manage MObject.  That
might be slow but easier to get going.

We're in smalltalk, after all, where such things is possible to do,
> unlike many other languages :)


Right on!


> >>
> >> - Stephen
> - Show quoted text -
>
>
> --
> Best regards,
> Igor Stasenko AKA sig.
>
>
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