Contract a filename, based on a relative path. Note that the resulting
path will never introduce
.. paths, as the presence of
symlinks means
../b may not reach
a/b if it starts
from
a/c. For a worked example see
this blog post.
The corresponding
makeAbsolute function can be found in
System.Directory.
makeRelative "/directory" "/directory/file.ext" == "file.ext"
Valid x => makeRelative (takeDirectory x) x `equalFilePath` takeFileName x
makeRelative x x == "."
Valid x y => equalFilePath x y || (isRelative x && makeRelative y x == x) || equalFilePath (y </> makeRelative y x) x
Windows: makeRelative "C:\\Home" "c:\\home\\bob" == "bob"
Windows: makeRelative "C:\\Home" "c:/home/bob" == "bob"
Windows: makeRelative "C:\\Home" "D:\\Home\\Bob" == "D:\\Home\\Bob"
Windows: makeRelative "C:\\Home" "C:Home\\Bob" == "C:Home\\Bob"
Windows: makeRelative "/Home" "/home/bob" == "bob"
Windows: makeRelative "/" "//" == "//"
Posix: makeRelative "/Home" "/home/bob" == "/home/bob"
Posix: makeRelative "/home/" "/home/bob/foo/bar" == "bob/foo/bar"
Posix: makeRelative "/fred" "bob" == "bob"
Posix: makeRelative "/file/test" "/file/test/fred" == "fred"
Posix: makeRelative "/file/test" "/file/test/fred/" == "fred/"
Posix: makeRelative "some/path" "some/path/a/b/c" == "a/b/c"