On Mon, Oct 22, 2012 at 8:42 PM, Steven D'Aprano <st...@pearwood.info> wrote: > If you do that, and the module directly or indirectly imports itself > while it is running as a script, you may run into trouble. But writing > a dual-purpose module that is usable as an importable module or as a > stand-alone script is not problematic in itself.
Yes. However, it is somewhat hard to guarantee that a module won't indirectly import itself for a large codebase. It certainly sometimes happens by accident. >> So use the first one always. > This is contrary to the advice given in the Fine Manual: > > http://docs.python.org/library/__main__.html > > > More from Python's creator, GvR, and the Effbot: > > http://www.artima.com/forums/flat.jsp?forum=106&thread=4829 > > http://effbot.org/pyfaq/tutor-what-is-if-name-main-for.htm It's very easy for me to overstate my case. Maybe I even have already, just because I wasn't taking very long to explain myself. I have concrete reasons to not use this form. It comes up very rarely, and is not a large issue. Heck, it's not even really worth making a big fuss over. But there is the occasional mess-up where it happens. I am also aware that what I prefer goes against idiom. But to me, this minor concrete use-case beats out idiom. After all, what is the benefit to following this particular idiom? I believe the answer is, "you get to use one .py file instead of two" -- and as I see it, the cases where circular imports might be a problem are precisely those where you don't care too much about the number of files, because you're writing a package anyway. As it happens, I sort of stumbled across this worldview when I was forced into separating modules from scripts with the new __main__ submodule system to make executable packages (So it's even possible for Pythonic code to forgo the name check). It really struck something in me, and I had a (subjective) realization that modules and scripts are fundamentally different, and that there's very little benefit to conflating them. I realize this isn't really a view that's mainstream for Python. Also, I realize it's not a particularly interesting realization -- any C# programmer would tell you this. And presumably, Pythonistas as a group would disagree. (As an aside, I find it interesting how much more beautiful GvR's code in that post becomes if you consider turning the common bits into a @main decorator). -- Devin _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
