On 11/12/2014 4:02 PM, John Ladasky wrote:
I have taught Python to several students over the past few years. As
I have worked with my students, I find myself bothered by the
programming idiom that we use to determine whether a module is being
executed or merely imported:
"if __name__ == '__main__':"
The use of two dunder tokens -- one as a name in a namespace, and the
other as a string, is intimidating. It exposes too much of Python's
guts. As such, I think that it is less Pythonic than we might want.
Myself, I've been programming in Python for a decade, and I still
haven't dug very deeply into what exactly __name__ means or does.
I would like to start a discussion about whether Python should
include a function which executes this evaluation, and hides all of
the unfriendly dunderish details. And if that's a good idea, I would
invite a discussion of how, exactly, it should be implemented. I'm
nowhere near proposing a PEP, but that may come later.
Functions have an implicit 'return None' at the end (which, in CPython,
become an explicit pair of bytecodes, even when the function already
ends with return something'. The simplest proposal is that modules have
an implicit "if __name__ == '__main__': main()" at the end. I think
this would not have to be added to the bytecode.
This magical invocation mimics C and some other languages, and I think
it works well.
--
Terry Jan Reedy
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