On Fri, 06 Aug 2010 15:37:04 +0200, Stefan Schwarzer wrote: [snip] > I can imagine a case where you might want to compare a > string with `is`: > > FORWARD = "forward" > BACKWARD = "backward" > > ... > > def func(direction=FORWARD): > if direction is FORWARD: > ... > elif direction is BACKWARD: > ... > else: > ... > > in case you expect people to specifically use the constants > you provided in the module. Here, the fact that FORWARD > actually is the string "forward" might be considered an > implementation detail. Using a string instead of an > `object()` has the advantage that it makes usage in error > messages easier. > > Actually, I've never seen such a use, as far as I remember. > What do other people here think? Is the code above, which > compares strings with `is`, bad style, and if yes, why? How > would you write the code instead?
Hey, that's a cute example, but . . . what a trap! Is it possible to document the use-the-object-not-the-string requirement loudly enough that people won't get caught? -- To email me, substitute nowhere->spamcop, invalid->net. -- http://mail.python.org/mailman/listinfo/python-list
