[project @ 1997-01-06 21:08:42 by simonpj]

[ghc-hetmet.git] / ghc / compiler / rename / RnNames.lhs

diff --git a/ghc/compiler/rename/RnNames.lhs b/ghc/compiler/rename/RnNames.lhs
index 069d710..5db5ead 100644 (file)
--- a/ghc/compiler/rename/RnNames.lhs
+++ b/ghc/compiler/rename/RnNames.lhs
@@ -12,7 +12,7 @@ module RnNames (
 
 IMP_Ubiq()
 
-import CmdLineOpts     ( opt_SourceUnchanged )
+import CmdLineOpts     ( opt_SourceUnchanged, opt_NoImplicitPrelude )
 import HsSyn   ( HsModule(..), HsDecl(..), FixityDecl(..), Fixity, Fake, InPat, IE(..), HsTyVar,
                  TyDecl, ClassDecl, InstDecl, DefaultDecl, ImportDecl(..), HsBinds, IfaceSig
                )
@@ -91,8 +91,13 @@ getGlobalNames m@(HsModule this_mod _ exports imports _ _ mod_loc)
 
     all_imports = prel_imports ++ imports
 
+       -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
+       -- because the former doesn't even look at Prelude.hi for instance declarations,
+       -- whereas the latter does.
     prel_imports | this_mod == pRELUDE ||
-                  explicit_prelude_import = []
+                  explicit_prelude_import ||
+                  opt_NoImplicitPrelude
+                = []
 
                 | otherwise               = [ImportDecl pRELUDE 
                                                         False          {- Not qualified -}
@@ -125,12 +130,7 @@ checkEarlyExit mod
 importsFromImportDecl :: RdrNameImportDecl
                      -> RnMG (RnEnv, ModuleAvails)
 
-       -- Check for "import M ()", and then don't even look at M.
-       -- This makes sense, and is actually rather useful for the Prelude.
-importsFromImportDecl (ImportDecl mod qual as_mod (Just (False,[])) loc)
-  = returnRn (emptyRnEnv, emptyModuleAvails)
-
-importsFromImportDecl (ImportDecl mod qual as_mod import_spec loc)
+importsFromImportDecl (ImportDecl mod qual_only as_mod import_spec loc)
   = pushSrcLocRn loc $
     getInterfaceExports mod                    `thenRn` \ (avails, fixities) ->
     filterImports mod import_spec avails       `thenRn` \ filtered_avails ->
@@ -140,7 +140,11 @@ importsFromImportDecl (ImportDecl mod qual as_mod import_spec loc)
                           ]
        fixities'        = [ (occ,fixity,provenance) | (occ,fixity) <- fixities ]
     in
-    qualifyImports mod qual as_mod (ExportEnv filtered_avails' fixities')
+    qualifyImports mod 
+                  True                 -- Want qualified names
+                  (not qual_only)      -- Maybe want unqualified names
+                  as_mod
+                  (ExportEnv filtered_avails' fixities')
   where
     set_name_prov name = setNameProvenance name provenance
     provenance = Imported mod loc
@@ -152,7 +156,8 @@ importsFromLocalDecls rec_exp_fn (HsModule mod _ _ _ fix_decls decls _)
   = foldlRn getLocalDeclBinders [] decls               `thenRn` \ avails ->
     mapRn fixityFromFixDecl fix_decls                  `thenRn` \ fixities ->
     qualifyImports mod 
-                  False        -- Not qualified
+                  False        -- Don't want qualified names
+                  True         -- Want unqualified names
                   Nothing      -- No "as M" part
                   (ExportEnv avails fixities)
   where
@@ -250,41 +255,52 @@ right qaulified names.  It also turns the @Names@ in the @ExportEnv@ into
 fully fledged @Names@.
 
 \begin{code}
-qualifyImports :: Module                               -- Improrted module
-              -> Bool                                  -- True <=> qualified import
+qualifyImports :: Module                               -- Imported module
+              -> Bool                                  -- True <=> want qualified import
+              -> Bool                                  -- True <=> want unqualified import
               -> Maybe Module                          -- Optional "as M" part 
               -> ExportEnv                             -- What's imported
               -> RnMG (RnEnv, ModuleAvails)
 
-qualifyImports this_mod qual as_mod (ExportEnv avails fixities)
+qualifyImports this_mod qual_imp unqual_imp as_mod (ExportEnv avails fixities)
   =    -- Make the qualified-name environments, checking of course for clashes
     foldlRn add_name emptyNameEnv avails                       `thenRn` \ name_env ->
     foldlRn (add_fixity name_env) emptyFixityEnv fixities      `thenRn` \ fixity_env ->
-
-       -- Deal with the "qualified" part; if not qualifies then add unqualfied bindings
-    if qual then
-       returnRn (RnEnv name_env fixity_env, mod_avail_env)
-    else
-       returnRn (RnEnv (unQualify name_env) (unQualify fixity_env), mod_avail_env)
-
+    returnRn (RnEnv name_env fixity_env, mod_avail_env)
   where
-    mod_avail_env  = unitFM this_mod avails
+    qual_mod = case as_mod of
+                 Nothing           -> this_mod
+                 Just another_name -> another_name
+
+    mod_avail_env  = unitFM qual_mod avails
 
     add_name name_env NotAvailable = returnRn name_env
     add_name name_env (Avail n ns) = foldlRn add_one name_env (n : ns)
 
     add_one :: NameEnv -> Name -> RnMG NameEnv
-    add_one env name = addOneToNameEnvRn env (Qual this_mod occ_name) name
+    add_one env name = add_to_env addOneToNameEnvRn env occ_name name
                     where
                        occ_name = nameOccName name
 
+    add_to_env add_fn env occ thing | qual_imp && unqual_imp = both
+                                   | qual_imp               = qual_only
+                                   | unqual_imp             = unqual_only
+                               where
+                                 unqual_only = add_fn env  (Unqual occ)        thing
+                                 qual_only   = add_fn env  (Qual qual_mod occ) thing
+                                 both        = unqual_only     `thenRn` \ env' ->
+                                               add_fn env' (Qual qual_mod occ) thing
+                       
     add_fixity name_env fixity_env (occ_name, fixity, provenance)
-       | maybeToBool (lookupFM name_env qual_name)     -- The name is imported
-       = addOneToFixityEnvRn fixity_env qual_name (fixity,provenance)
-       | otherwise                             -- It ain't imported
+       | maybeToBool (lookupFM name_env rdr_name)      -- It's imported
+       = add_to_env addOneToFixityEnvRn fixity_env occ_name (fixity,provenance)
+       | otherwise                                     -- It ain't imported
        = returnRn fixity_env
        where
-         qual_name = Qual this_mod occ_name
+               -- rdr_name is a name by which the thing is guaranteed to be known,
+               -- *if it is imported at all*
+         rdr_name | qual_imp  = Qual qual_mod occ_name
+                  | otherwise = Unqual occ_name
 \end{code}
 
 unQualify adds an Unqual binding for every existing Qual binding.