On Mon, 2005-04-25 at 21:21 -0400, Brian Beck wrote:

Donovan Baarda wrote:

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Agreed. I don't find any switch syntaxes better than if/elif/else. Speed benefits belong in implementation optimisations, not new bad syntax.

I posted this 'switch' recipe to the Cookbook this morning, it saves some typing over the if/elif/else construction, and people seemed to like it. Take a look: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/410692

Very clever... you have shown that current python syntax is capable of almost exactly replicating a C case statement. My only problem is C case statements are ugly. A simple if/elif/else is much more understandable to me. The main benefit in C of case statements is the compiler can optimise them. This copy of a C case statement will be slower than an if/elif/else, and just as ugly :-) -- Donovan Baarda http://minkirri.apana.org.au/~abo/

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"Greg" == Greg Ewing writes:

Greg> Two things are mildly annoying about if-elif chains as a Greg> substitute for a switch statement: Greg> 1) Repeating the name of the thing being switched on all the Greg> time, and the operator being used for comparison. What's worse, to my mind, is the not infrequent case where the thing being switched on or the operator changes. Sure, that's bad style, but sometimes you have to read other people's code like that. -- School of Systems and Information Engineering http://turnbull.sk.tsukuba.ac.jp University of Tsukuba Tennodai 1-1-1 Tsukuba 305-8573 JAPAN Ask not how you can "do" free software business; ask what your business can "do for" free software.

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"Guido" == Guido van Rossum writes:

Guido> You mean like this? if x > 0: ...normal case... elif y > 0: ....abnormal case... else: ...edge case... The salient example! If it's no accident that those conditions are mutually exclusive and exhaustive, doesn't that code require at least a comment saying so, and maybe even an assertion to that effect? Where you can use a switch, it gives both, and throws in economy in both source and object code as a bonus. Not a compelling argument---your example shows switches are not universally applicable---but it's a pretty good deal. Guido> You have guts to call that bad style! :-) Exaggeration in defense of elegance is no vice.<wink> -- School of Systems and Information Engineering http://turnbull.sk.tsukuba.ac.jp University of Tsukuba Tennodai 1-1-1 Tsukuba 305-8573 JAPAN Ask not how you can "do" free software business; ask what your business can "do for" free software.

Exaggeration in defense of elegance is no vice.<wink>

Maybe not, but it still sounds like BS to me. -- --Guido van Rossum (home page: http://www.python.org/~guido/)