X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=System%2FFilePath.hs;h=4ae4a88c61adda2697a538909c4eb13ae7072913;hb=51f27f26931c97ab4965806ef08842be4465e83c;hp=3fead9be87f0da048bc1b4a3ac453c8c266febe3;hpb=bb101834420322740e520292b34ef5a8b31ddc8b;p=ghc-base.git

diff --git a/System/FilePath.hs b/System/FilePath.hs
index 3fead9b..4ae4a88 100644
--- a/System/FilePath.hs
+++ b/System/FilePath.hs
@@ -26,6 +26,7 @@ module System.FilePath
          , changeFileExt
          , isRootedPath
          , isAbsolutePath
+         , dropAbsolutePrefix
 
          , pathParents
          , commonParent
@@ -228,6 +229,18 @@ isAbsolutePath (c:_)       | isPathSeparator c = True
 #endif
 isAbsolutePath _ = False
 
+-- | If the function is applied to an absolute path then it returns a
+-- local path obtained by dropping the absolute prefix from the path.
+-- Under Windows the prefix is @\"\\\"@, @\"c:\"@ or @\"c:\\\"@.
+-- Under Unix the prefix is always @\"\/\"@.
+dropAbsolutePrefix :: FilePath -> FilePath
+dropAbsolutePrefix (c:cs) | isPathSeparator c = cs
+#ifdef mingw32_TARGET_OS
+dropAbsolutePrefix (_:':':c:cs) | isPathSeparator c = cs  -- path with drive letter
+dropAbsolutePrefix (_:':':cs)                       = cs
+#endif
+dropAbsolutePrefix cs = cs
+
 -- | Gets this path and all its parents.
 -- The function is useful in case if you want to create 
 -- some file but you aren\'t sure whether all directories