[Python-Dev] Re: Activating `-i' from inside a script?

2003年6月28日 17:40:11 -0400

> On c.l.py someone asked about forcing a tailend interactive shell from
> within the program. Try Melhase proposed:
>> import os
>> if __name__ == '__main__':
> discrepancy = True
> if discrepancy:
> os.environ['PYTHONINSPECT'] = "why yes, i'd like that"
>> but observed that it doesn't work because the environment variable is only
> checked at program start.
>> This change to Modules/main.c makes the above work:
>> % cvs diff main.c
> Index: main.c
> ===================================================================
> RCS file: /cvsroot/python/python/dist/src/Modules/main.c,v
> retrieving revision 1.77
> diff -c -r1.77 main.c
> *** main.c 30 Mar 2003 17:09:58 -0000 1.77
> --- main.c 27 Jun 2003 11:50:42 -0000
> ***************
> *** 418,423 ****
> --- 418,428 ----
> filename != NULL, &cf) != 0;
> }
>> + /* also check at the end in case the program set PYTHONINSPECT */
> + if (!saw_inspect_flag &&
> + (p = Py_GETENV("PYTHONINSPECT")) && *p != '0円')
> + inspect = 1;
> + 
> if (inspect && stdin_is_interactive &&
> (filename != NULL || command != NULL))
> /* XXX */
>> I can't see that it would affect the functioning of any programs other than
> those which set PYTHONINSPECT now. (But why would they do that and what's
> the likelihood such programs exist?)
>> Any chance this could be squeezed in? It seems rather elegant:
>> try:
> something which fails
> except:
> os.environ["PYTHONINSPECT"] = 1
> raise
>> (I know we're at beta1, and the programmer could re-run with -i. But
> still...)

Looks harmless to me. Thomas Heller's alternative really does
something different. Skip can check it in.
--Guido van Rossum (home page: http://www.python.org/~guido/)