I tried writing a little command-line utility to find the relative path of one thing from another thing (with Unix-like systems in mind). ...
FWIW, there's logic to do something like this in my URI module [1]. Bear in mind that there is not, in general, a unique solution (e.g. in extremis, the absolute path of the target might be a legitimate solution, regardless of the base).
[1] http://www.ninebynine.org/Software/HaskellUtils/Network/URI.hs
There's also a slightly later copy in the Haskell libraries CVS, which I believe is due to ship with the next GHC release. Look for function relativeFrom.
See also module URITest.hs [2], for examples of relative paths created by this algorithm (look for function testRelSplit).
[2] http://www.ninebynine.org/Software/HaskellUtils/Network/URITest.hs
#g --
At 15:17 20/01/05 -0500, Mark Carroll wrote:
I tried writing a little command-line utility to find the relative path of one thing from another thing (with Unix-like systems in mind). For example,
$ ./pathfromof /etc/init.d/ /etc/X11/XF86Config-4 ../X11/XF86Config-4 $ ./pathfromof /tmp/baz/ /tmp/foo/ . $ ls -l /tmp/baz lrwxr-xr-x 1 markc markc 8 2005-01-20 12:01 /tmp/baz -> /tmp/foo
It turned out surprisingly complex, though, and doesn't feel very neat or tidy at all, nor is it very portable given that I couldn't find generic library functions for manipulating bits of filepaths. Anyhow, it's at http://www.chiark.greenend.org.uk/~markc/PathFromOf.hs and may yet have egregious bugs.
It seems to me like it could certainly be improved in various ways. If anyone has any thoughts, as to how I could improve my style, make more use of standard libraries, etc., I'd certainly appreciate them.
Thanks, Mark _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
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