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

[Samuel Gougeon]

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\*

Samuel