George Sakkis wrote:
Using special objects to be lazy with your algorithm will never be wise.
s/lazy/elegant
To each his own, but your substitution fails to convince me that magic values are more readable than using a "valid" flag variable.
-1 Let's not provide features for misguided programming idioms.
I don't consider Dijkstra's shortest path algorithm and the others mentioned in PEP 326 as examples of misguided programming idioms.
The algorithm isn't misguided. The use of a magic constant is misguided. Please don't confuse the language I choose. The only way it's safe is if you if-check the output values from your algorithm, and then there is no reason to have a special value, just use a flag. If you are not doing the if-check, then you are using a misguided programming idiom (unless you have proven for all possible inputs, there is a solution to your algorithm.) While in the examples in PEP 326, it's vaguely clear that it's not a problem. I imagine many uses that behave like this: minval = Max for i in vals: if i < minval: minval = i Which is a failure of design championed by a programming idiom you want to create. At least, if they attempt to pick some "Max" value, they will have the opportunity to realize the mistake rather than assume "it's the Python way". Furthermore, the PEP's examples aren't compelling because you can roll-your-own easily if you want such a thing, and since I consider it strictly bad to use them as output values, it makes no difference if its a built-in or not.
Besides, the reasons for rejection read more like a lukewarm -0 ("not that useful, easily implemented, can't decide
Perhaps, but I for one think it's silly. -Scott -- Scott Dial scott@scottdial.com scodial@cs.indiana.edu