[Scilab-Dev] Hijacking built-in "set" almost works...

[Stéphane Mottelet]

Le 01/03/2018 à 21:57, Stéphane Mottelet a écrit :
> Hello,
>
>> Le 1 mars 2018 à 20:18, Samuel Gougeon <sgougeon at free.fr> a écrit :
>>
>>> Le 01/03/2018 à 20:09, Stéphane Mottelet a écrit :
>>> Hello,
>>>
>>> I have tried to implement a (naïve) hijacking mechanism that works *like a charm* under scilab 5.5.2:
>>>
>>> newfun('scilab_set',funptr('set'));
>>> clearfun('set');
>>> function set(varargin)
>>>     scilab_set(varargin(:))
>>>     printf("...\n")
>>> endfunction
>>> // test the hijacked "set"
>>> f=gcf()
>>> set(f,"tag","1")
>>> f.tag="2"
>>>
>>> When I test this under  6.0.0 or 6.0.1, the last line always crashes Scilab. Is there an evident reason why ? When trying this on the command line (scilab -nw)
>>>
>>>> --> set(f,"tag","1")
>>>> ...
>>>>
>>>> --> f.tag="2"
>>>> ...
>>>> /Applications/scilab-6.0.1.app/Contents/MacOS/bin/scilab: line 972: 27117 Illegal instruction: 4  "$SCILABBIN" "$@"
>>> I can see that the problem occurs *after* the insertion code f.tag="2" has delegated the operation to the hijacked "set", hence the crash occurs in the built-in function which does the insertion. In order to understand why this crash occurs (under Linux or OSX), I would like to know which module is in charge of the insertion for handles (a kind of %h_i but built-in) ?
>> You may have a look at
>> SCI\modules\graphic_objects\src\cpp\setGraphicObjectProperty.cpp
>> and
>> SCI\modules\graphic_objects\src\java\org\scilab\modules\graphic_objects\*
> Hmm, the crash occurs *after* the property has been set. So my question was rather about the generic code that handles field insertion, which is delegated to “set” for handles.
>
> S.
>

I have localized many methods for handle type in 
modules/ast/src/cpp/types/graphichandle.cpp. Although I don't know much 
of C++, I can see that GraphicHandle::invoke is delegated to the 
overloaded %h_e macro, hence is an extraction method, but I am not able 
to find any *insertion* method in this file. Maybe someone knows ?

S.