[project @ 2005-01-11 16:04:08 by simonmar]

[ghc-base.git] / System / FilePath.hs

diff --git a/System/FilePath.hs b/System/FilePath.hs
index bb85ba1..a970486 100644 (file)
--- a/System/FilePath.hs
+++ b/System/FilePath.hs
@@ -1,3 +1,5 @@
+{-# OPTIONS_GHC -fno-implicit-prelude #-}
+
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  System.FilePath
@@ -24,6 +26,7 @@ module System.FilePath
          , changeFileExt
          , isRootedPath
          , isAbsolutePath
+         , dropAbsolutePrefix
 
          , pathParents
          , commonParent
@@ -43,9 +46,15 @@ module System.FilePath
         , dllExtension
          ) where
 
+#ifdef __GLASGOW_HASKELL__
+import GHC.Base
+import GHC.IOBase(FilePath)
+import GHC.Num
+#else
 import Prelude -- necessary to get dependencies right
-
-import Data.List(intersperse)
+#endif
+import Data.Maybe
+import Data.List
 
 --------------------------------------------------------------
 -- * FilePath
@@ -139,7 +148,7 @@ splitFilePath p =
       (_:dir) -> dir++drive
 
 -- | The 'joinFileName' function is the opposite of 'splitFileName'. 
--- It joins directory and file names to form complete file path.
+-- It joins directory and file names to form a complete file path.
 --
 -- The general rule is:
 --
@@ -147,7 +156,7 @@ splitFilePath p =
 -- >   where
 -- >     (dir,basename) = splitFileName path
 --
--- There might be an exeptions to the rule but in any case the
+-- There might be an exceptions to the rule but in any case the
 -- reconstructed path will refer to the same object (file or directory).
 -- An example exception is that on Windows some slashes might be converted
 -- to backslashes.
@@ -160,7 +169,7 @@ joinFileName dir fname
   | otherwise                  = dir++pathSeparator:fname
 
 -- | The 'joinFileExt' function is the opposite of 'splitFileExt'.
--- It joins file name and extension to form complete file path.
+-- It joins a file name and an extension to form a complete file path.
 --
 -- The general rule is:
 --
@@ -210,8 +219,8 @@ isRootedPath (_:':':c:_) | isPathSeparator c = True  -- path with drive letter
 #endif
 isRootedPath _ = False
 
--- | Returns True if this path\'s meaning is independent of any OS
--- "working directory", False if it isn\'t.
+-- | Returns 'True' if this path\'s meaning is independent of any OS
+-- \"working directory\", or 'False' if it isn\'t.
 isAbsolutePath :: FilePath -> Bool
 #ifdef mingw32_TARGET_OS
 isAbsolutePath (_:':':c:_) | isPathSeparator c = True
@@ -220,10 +229,22 @@ 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 
--- in the path exists or if you want to search upward for some file.
+-- in the path exist or if you want to search upward for some file.
 -- 
 -- Some examples:
 --
@@ -235,9 +256,6 @@ isAbsolutePath _ = False
 -- >  pathParents "dir1"       == [".", "dir1"]
 -- >  pathParents "dir1/dir2"  == [".", "dir1", "dir1/dir2"]
 --
--- In the above examples \"\/\" isn\'t included in the list 
--- because you can\'t create root directory.
---
 -- \[Windows\]
 --
 -- >  pathParents "c:"             == ["c:."]
@@ -247,7 +265,7 @@ isAbsolutePath _ = False
 -- >  pathParents "c:dir1"         == ["c:.","c:dir1"]
 -- >  pathParents "dir1\\dir2"     == [".", "dir1", "dir1\\dir2"]
 --
--- Note that if the file is relative then the the current directory (\".\") 
+-- Note that if the file is relative then the current directory (\".\") 
 -- will be explicitly listed.
 pathParents :: FilePath -> [FilePath]
 pathParents p =
@@ -386,7 +404,7 @@ searchPathSeparator = ':'
 
 -- ToDo: This should be determined via autoconf (AC_EXEEXT)
 -- | Extension for executable files
--- (typically @\"\"@ on Unix and @\".exe\"@ on Windows or OS\/2)
+-- (typically @\"\"@ on Unix and @\"exe\"@ on Windows or OS\/2)
 exeExtension :: String
 #ifdef mingw32_TARGET_OS
 exeExtension = "exe"
@@ -396,7 +414,7 @@ exeExtension = ""
 
 -- ToDo: This should be determined via autoconf (AC_OBJEXT)
 -- | Extension for object files
--- (typically @\".o\"@ on Unix and @\".obj\"@ on Windows)
+-- (typically @\"o\"@ on Unix and @\"obj\"@ on Windows)
 objExtension :: String
 #ifdef mingw32_TARGET_OS
 objExtension = "obj"
@@ -405,7 +423,7 @@ objExtension = "o"
 #endif
 
 -- | Extension for dynamically linked (or shared) libraries
--- (typically @\".so\"@ on Unix and @\".dll\"@ on Windows)
+-- (typically @\"so\"@ on Unix and @\"dll\"@ on Windows)
 dllExtension :: String
 #ifdef mingw32_TARGET_OS
 dllExtension = "dll"