[Python-Dev] about line numbers

[Christian Tismer]

Vladimir Marangozov wrote:
...
> I wrote a very rough first implementation of this idea. The files are at:
> 
> http://sirac.inrialpes.fr/~marangoz/python/lineno/
> 
> Basically, what I did is:
> 
> 1) what I said :-)
> 2) No more SET_LINENO
> 3) In tracing mode, a copy of the original code is put in an additional
>    slot (co_tracecode) of the code object. Then it's overwritten with
>    CALL_TRACE opcodes at the locations returned by PyCode_Line2Addr.

I'd rather keep the original code object as it is, create a copy
with inserted breakpoints and put that into the frame slot.
Pointing back to the original from there.

Then I'd redirect the code from the CALL_TRACE opcode completely
to a user-defined function.
Getting rid of the extra code object would be done by this function
when tracing is off. It also vanishes automatically when the frame
is released.

> a) how to deallocate the modified code string when tracing is off

By making the copy a frame property which is temporary, I think.
Or, if tracing should work for all frames, by pushing the original
in the back of the modified. Both works.

ciao - chris

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