[Python-Dev] Improve Python for embedding (original) (raw)

Tom Emerson tree at basistech.com
Mon Dec 22 14:40:12 EST 2003

Thomas Heller writes:

I find the current situation when 'embedding' Python rather unsatisfying.

Indeed. See patch 849278 for some of the work we did to deal with this.

1. Careful preparation (hacking?) of environment variables is needed to avoid that PyInitialize() takes the default actions needed for the standard Python interpreter (for example, to avoid the default sys.path).

I've done this in the patches submitted (by a coworker) above. The idea is to separate the embedded interpreter completely from the environment.

2. A suggestion from /F on c.l.p was to change pythonw.exe so that instead of hiding all output to stderr a console window would be opened to show the tracebacks. This requires to construct an object with a 'write' method doing all this magic, and it must be done after the call to PyInitialize() and before PyRunSimpleFile(). Now, looking at the code of PyMain(), it seems impossible without rewriting most of the code.

Yes, this is a problem with the embedded interpreter where errors may be written to stderr without regard to the calling application. Further, it is possible for the interpreter to call abort(), which is even worse.

Possible improvements I currently can think of are:

- Provide a function like PyInitializeEx(), which accepts parameters specifying an initial sys.path, optimize flag, verbose flag, and so on.

See the patch.

- Split PyMain() into 2 functions PyMainPrepare() and PyMainRun(), or let PyMain() accept a callback function which will be called jsut after PyInitialize() has been run.

Yup.

I'm not ready to write a PEP, but if there are people sharing this feeling I would suggest we create a wiki entry somewhere acting as a temporary brainstorming area.

Absolutely: count me in.

-tree

-- Tom Emerson Basis Technology Corp. Software Architect http://www.basistech.com "Beware the lollipop of mediocrity: lick it once and you suck forever"

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