Pythonic Idiom For Searching An Include Path

[Jorgen Grahn]

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.   .  .
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