[Vm-dev] SmartSyntaxPlugins simulation whitewash

Eliot Miranda eliot.miranda at gmail.com
Thu Sep 30 17:30:37 UTC 2010

Hi All,

    I just read Anthony Hallinan's most informative comment to
SmartSyntaxPlugin class>>simulatorClass which says that
        "By default SmartSyntaxInterpreterPlugin answers nil because methods
in these plugins
         are intended to be embedded in code that pushes and pops from the
stack and therefore
         cannot be run independently.  This wrapper code is generated when
translated to C.  But,
         unfortunately, this code is missing during simulation.  There was
an attempt to simulate this,
         but only the prologue code (getting arg from the stack) is
simulated (see simulatePrologInContext:).
        The epologue code (popping args and pushing result) is not.  So I am
making this nil until this can be fixed.
Also, beware that primitive methods that take no args exactly match their
primitive name (faking out
        InterpreterSimulator>>callExternalPrimitive:).  They should only be
called from within wrapper code that
        simulates the prologue and epilogue.  Primitive method that take
args don't have this accidental matching
        problem since their names contain colons while their primitive names
do not. - ajh 8/21/2002"

Strikes me that what needs to be done is to throw away the tricky
implementation of Object>>#primitive:parameters:receiver:, replacing it by a
simple direct implementation, and putting a wrapper around each
SmartSyntaxPlugin primitive as its installed whose job it is to check for
success and if so, cut back the stack and convert the result.  Anyone
interested who's not also hugely busy?

If so, focus on making LargeIntegersPlugin work using 22 factorial
printString as a test case.

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