[project @ 2005-11-04 15:48:25 by simonmar]

- Add support for the GHC_PACKAGE_PATH environment variable, which
  specifies a :-separated (;-separated on Windows) list of package
  database files.  If the list ends in : (; on Windows), then the
  normal user and global databases are added.

  GHC_PACKAGE_PATH is searched left-to-right for packages, like
  $PATH, but unlike -package-conf flags, which are searched
  right-to-left.  This isn't ideal, but it seemed the least worst to me
  (command line flags always override right-to-left (except -i),
  whereas the PATH environment variable overrides left-to-right, I chose
  to follow the environment variable convention).  I can always change
  it if there's an outcry.

- Rationalise the interpretation of --user, --global, and -f on the
  ghc-pkg command line.  The story is now this: --user and --global
  say which package database to *act upon*, they do not change the
  shape of the database stack.  -f pushes a database on the stack, and
  also requests that the specified database be the one to act upon, for
  commands that modify the database.  If a database is already on the stack,
  then -f just selects it as the one to act upon.

  This means you can have a bunch of databases in GHC_PACKAGE_PATH, and
  use -f to select the one to modify.

1 files changed, 35 insertions, 0 deletions

diff --git a/ghc/compiler/utils/Util.lhs b/ghc/compiler/utils/Util.lhs
index 0911dba841..1598c124fe 100644
--- a/ghc/compiler/utils/Util.lhs
+++ b/ghc/compiler/utils/Util.lhs
@@ -70,6 +70,7 @@ module Util (
 	replaceFilenameSuffix, directoryOf, filenameOf,
 	replaceFilenameDirectory,
 	escapeSpaces, isPathSeparator,
+	parseSearchPath,
 	normalisePath, platformPath, pgmPath,
     ) where
 
@@ -950,6 +951,40 @@ isPathSeparator ch =
   ch == '/'
 #endif
 
+--------------------------------------------------------------
+-- * Search path
+--------------------------------------------------------------
+
+-- | The function splits the given string to substrings
+-- using the 'searchPathSeparator'.
+parseSearchPath :: String -> [FilePath]
+parseSearchPath path = split path
+  where
+    split :: String -> [String]
+    split s =
+      case rest' of
+        []     -> [chunk] 
+        _:rest -> chunk : split rest
+      where
+        chunk = 
+          case chunk' of
+#ifdef mingw32_HOST_OS
+            ('\"':xs@(_:_)) | last xs == '\"' -> init xs
+#endif
+            _                                 -> chunk'
+
+        (chunk', rest') = break (==searchPathSeparator) s
+
+-- | A platform-specific character used to separate search path strings in 
+-- environment variables. The separator is a colon (\":\") on Unix and Macintosh, 
+-- and a semicolon (\";\") on the Windows operating system.
+searchPathSeparator :: Char
+#if mingw32_HOST_OS || mingw32_TARGET_OS
+searchPathSeparator = ';'
+#else
+searchPathSeparator = ':'
+#endif
+
 -----------------------------------------------------------------------------
 -- Convert filepath into platform / MSDOS form.