a particularly active member of the Distutils-SIG brought the global '__debug__' flag to my attention, since I (and thus my code) didn't know if calling 'py_compile.compile()' would result in a ".pyc" or a ".pyo" file. It appears that, using __debug__, you can determine what you're going to get. Cool!

However, it doesn't look like you can *choose* what you're going to get. Is this correct? Ie. does the presence/absence of -O when the interpreter starts up *completely* decide how code is compiled?

Correct. You (currently) can't change the opt setting of the compiler. (It was part of the compiler restructuring to give more freedom here; this has been pushed back to 1.7.)

Also, can I rely on __debug__ being there in the future? How about in the past? I still occasionally ponder making Distutils compatible with Python 1.5.1.

__debug__ is as old as the assert statement, going back to at least 1.5.0. --Guido van Rossum (home page: http://www.python.org/~guido/)

a particularly active member of the Distutils-SIG brought the global '__debug__' flag to my attention, since I (and thus my code) didn't know if calling 'py_compile.compile()' would result in a ".pyc" or a ".pyo" file. It appears that, using __debug__, you can determine what you're going to get. Cool!

However, it doesn't look like you can *choose* what you're going to get. Is this correct? Ie. does the presence/absence of -O when the interpreter starts up *completely* decide how code is compiled?

Correct. You (currently) can't change the opt setting of the compiler. (It was part of the compiler restructuring to give more freedom here; this has been pushed back to 1.7.)

Also, can I rely on __debug__ being there in the future? How about in the past? I still occasionally ponder making Distutils compatible with Python 1.5.1.

__debug__ is as old as the assert statement, going back to at least 1.5.0. --Guido van Rossum (home page: http://www.python.org/~guido/)