[project @ 2000-10-18 12:47:55 by sewardj]

[ghc-hetmet.git] / ghc / compiler / main / Finder.lhs

diff --git a/ghc/compiler/main/Finder.lhs b/ghc/compiler/main/Finder.lhs
index 8408501..7f91297 100644 (file)
--- a/ghc/compiler/main/Finder.lhs
+++ b/ghc/compiler/main/Finder.lhs
@@ -7,7 +7,8 @@
 module Finder (
     Finder,            -- =  ModuleName -> IO (Maybe (Module, ModuleLocation))
     newFinder,                 -- :: PackageConfigInfo -> IO Finder, 
-    ModuleLocation(..)
+    ModuleLocation(..),
+    mkHomeModuleLocn
   ) where
 
 #include "HsVersions.h"
@@ -27,9 +28,22 @@ import IO
 import Monad
 \end{code}
 
+The Finder provides a thin filesystem abstraction to the rest of the
+compiler.  For a given module, it knows (a) which package the module
+lives in, so it can make a Module from a ModuleName, and (b) where the
+source, interface, and object files for a module live.
+
 \begin{code}
 type Finder = ModuleName -> IO (Maybe (Module, ModuleLocation))
 
+-- For a module in another package, the hs_file and obj_file
+-- components of ModuleLocation are undefined.  
+
+-- The locations specified by a ModuleLocation may or may not
+-- correspond to actual files yet: for example, even if the object
+-- file doesn't exist, the ModuleLocation still contains the path to
+-- where the object file will reside if/when it is created.
+
 data ModuleLocation
    = ModuleLocation {
        hs_file  :: FilePath,
@@ -103,28 +117,28 @@ maybeHomeModule mod_name = do
        lhs = basename ++ ".lhs"
 
    case lookupFM home_cache hs of {
-       Just path -> mkHomeModuleLocn mod_name basename path hs;
+       Just path -> mkHomeModuleLocn mod_name (path ++ '/':basename) hs;
        Nothing ->
 
    case lookupFM home_cache lhs of {
-       Just path ->  mkHomeModuleLocn mod_name basename path lhs;
+       Just path ->  mkHomeModuleLocn mod_name (path ++ '/':basename) lhs;
        Nothing -> return Nothing
 
    }}
 
-mkHomeModuleLocn mod_name basename path source_fn = do
+mkHomeModuleLocn mod_name basename source_fn = do
 
    -- figure out the .hi file name: it lives in the same dir as the
    -- source, unless there's a -ohi flag on the command line.
    ohi    <- readIORef output_hi
    hisuf  <- readIORef hi_suf
    let hifile = case ohi of
-                  Nothing -> path ++ '/':basename ++ hisuf
+                  Nothing -> basename ++ hisuf
                   Just fn -> fn
 
    -- figure out the .o file name.  It also lives in the same dir
    -- as the source, but can be overriden by a -odir flag.
-   o_file <- odir_ify (path ++ '/':basename ++ '.':phaseInputExt Ln)
+   o_file <- odir_ify (basename ++ '.':phaseInputExt Ln)
 
    return (Just (mkHomeModule mod_name,
                  ModuleLocation{