[Python-Dev] ANN: PEP 335: Overloadable Boolean Operators (original) (raw)

Greg Ewing greg at cosc.canterbury.ac.nz
Wed Sep 15 03:15:09 CEST 2004

"Phillip J. Eby" <pje at telecommunity.com>:

So, something like this:

query("x and y or z") isn't "code that performs database queries"?

Yes, but it's not Python code - it's SQL code wrapped in a string wrapped in Python code. I want just Python code.

My main concern about the PEP is that it adds overhead to all logical operations, but the feature will only benefit code that hasn't yet been written.

The overhead shouldn't be substantially worse than that already incurred by all the other operators being overloadable. Also, realistically, how much code do you think has boolean operations as a speed bottleneck? I find it hard to imagine what such code would be like.

I also fear that as a result, people will start writing complex if-then blocks to "optimize" performance of conditionals to get them back to where they were before the facility was added.

If people do that, they're guilty of premature optimisation if they haven't actually measured the speed of their code and found an actual problem with it. I expect such cases will be extremely rare if they occur at all.

Greg Ewing, Computer Science Dept, +--------------------------------------+ University of Canterbury, | A citizen of NewZealandCorp, a | Christchurch, New Zealand | wholly-owned subsidiary of USA Inc. | greg at cosc.canterbury.ac.nz +--------------------------------------+

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