Which Python implementation am I using?

[Laura Creighton]

In a message of Sat, 08 Aug 2015 03:27:04 +1000, "Steven D'Aprano" writes:
>
>    def jython():
>        t = platform.java_ver()
>        return (t and t[0]) or ('java' in sys.platform.lower())

Around here if we cannot find platform.python_implemention()
we just look for sys.platform.startswith('java')

Are there any cases where you need platform.java_ver() ?

I don't know about IronPython

>How about PyPy, Stackless, or others?

PyPy has platform.python_implementation these days as well.  If you
cannot find it, look for '__pypy__' in sys.builtin_module_names

For detecting Stackless my PYTHONSTARTUP just tries to import stackless.

Detecting Cygwin may be important for you.  It's a real mess.
platform.system usually gives you stuff like: CYGWIN_NT-5.1
but, alas, sometimes it just gives you 'Windows'.
os.name sometimes gives you 'nt' -- but sometimes it gives you 'posix'.

I've played whack-a-mole with this one for a while, and still don't
like any of our solutions.  And the customer threw out his windows
systems and replaced them with Macs, so the problem now is moot for me.

Laura