On Thu, 2010-06-24, Nobody wrote: > On Wed, 23 Jun 2010 17:27:16 -0500, Tim Daneliuk wrote: > >> Given a program 'foo' that takes a command line argument '-I >> includefile', I want to be able to look for 'includefile' in a path >> specified in an environment variable, 'FOOPATH'. >> >> I'd like a semantic that says: >> >> "If 'includefile' contains one or more path separator characters, >> ignore 'FOOPATH'. If it contains no path separators, look for it in >> the paths specified by 'FOOPATH', beginning with the leftmost path >> first." >> >> Is there a standard Pythonic idiom for doing this or do I need to cook >> up my own. > > There isn't an idiom. > > There are a surprising number of choices for such a simple task, e.g. > whether the search path is used for relative paths containing a separator, > whether you stop at the first file which exists or the first file which > meets other criteria (e.g. suitable permissions), whether default > locations come first or last, what happens if a default location is > included in the search path, etc.
Another favorite is whether relative paths are relative to your current directory, or to the location of whatever file this is to be included /into/. For an example where it mattered (to C compilers), google for the paper "recursive make considered harmful". It took compiler writers decades to realize what the best choice was there. (By the way, -I commonly means "search this directory for include files" rather than "include this file". You may want to avoid confusing people by choosing another letter, like -i.) /Jorgen -- // Jorgen Grahn <grahn@ Oo o. . . \X/ snipabacken.se> O o . -- http://mail.python.org/mailman/listinfo/python-list
