[project @ 2001-03-01 14:26:00 by simonmar]

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

diff --git a/ghc/compiler/main/HscTypes.lhs b/ghc/compiler/main/HscTypes.lhs
index f52f2cd..ec70d32 100644 (file)
--- a/ghc/compiler/main/HscTypes.lhs
+++ b/ghc/compiler/main/HscTypes.lhs
@@ -18,7 +18,7 @@ module HscTypes (
 
        IfaceDecls, mkIfaceDecls, dcl_tycl, dcl_rules, dcl_insts,
 
-       VersionInfo(..), initialVersionInfo,
+       VersionInfo(..), initialVersionInfo, lookupVersion,
 
        TyThing(..), isTyClThing, implicitTyThingIds,
 
@@ -74,7 +74,7 @@ import CoreSyn                ( IdCoreRule )
 
 import FiniteMap       ( FiniteMap )
 import Bag             ( Bag )
-import Maybes          ( seqMaybe )
+import Maybes          ( seqMaybe, orElse )
 import Outputable
 import SrcLoc          ( SrcLoc, isGoodSrcLoc )
 import Util            ( thenCmp, sortLt )
@@ -339,13 +339,19 @@ data VersionInfo
                -- The version of an Id changes if its fixity changes
                -- Ditto data constructors, class operations, except that the version of
                -- the parent class/tycon changes
+               --
+               -- If a name isn't in the map, it means 'initialVersion'
     }
 
 initialVersionInfo :: VersionInfo
 initialVersionInfo = VersionInfo { vers_module  = initialVersion,
                                   vers_exports = initialVersion,
                                   vers_rules   = initialVersion,
-                                  vers_decls   = emptyNameEnv }
+                                  vers_decls   = emptyNameEnv
+                       }
+
+lookupVersion :: NameEnv Version -> Name -> Version
+lookupVersion env name = lookupNameEnv env name `orElse` initialVersion
 
 data Deprecations = NoDeprecs
                  | DeprecAll DeprecTxt                         -- Whole module deprecated