On Fri, Mar 22, 2013 at 3:42 PM, Gregory P. Smith firstname.lastname@example.org wrote:
On Fri, Mar 22, 2013 at 3:31 PM, Ronny Pfannschmidt Ronny.Pfannschmidt@gmx.de wrote:
while reviewing urllib.parse i noticed a pretty ugly pattern
many functions had an attached global and in their own code they would compile an regex on first use and assign it to that global
its clear that compiling a regex is expensive, so having them be compiled later at first use would be of some benefit
It isn't expensive to do, it is expensive to do repeatedly for no reason. Thus the use of compiled regexes. Code like this would be better off refactored to reference a precompiled global rather than conditionally check if it needs compiling every time it is called.
Alternatively, if there are a lot of different regexes, it may be better to rely on the implicit cache inside the re module.