[project @ 2004-02-24 16:44:26 by simonpj]

---------------------------------------
      Allow constructors to be specified in hi-boot files
	  ---------------------------------------

diff --git a/ghc/compiler/parser/Parser.y.pp b/ghc/compiler/parser/Parser.y.pp
index 8276bb5..fd7dab7 100644 (file)
--- a/ghc/compiler/parser/Parser.y.pp
+++ b/ghc/compiler/parser/Parser.y.pp
@@ -327,10 +327,12 @@ ifacedecl :: { HsDecl RdrName }
                 { SigD (Sig $1 $3) }
        | 'type' syn_hdr '=' ctype      
                { let (tc,tvs) = $2 in TyClD (TySynonym tc tvs $4) }
-       | 'data' tycl_hdr
-               { TyClD (mkTyData DataType (unLoc $2) [] Nothing) }
-       | 'newtype' tycl_hdr
+       | 'data' tycl_hdr constrs       -- No deriving in hi-boot
+               { TyClD (mkTyData DataType (unLoc $2) (reverse (unLoc $3)) Nothing) }
+       | 'newtype' tycl_hdr            -- Constructor is optional
                { TyClD (mkTyData NewType (unLoc $2) [] Nothing) }
+       | 'newtype' tycl_hdr '=' newconstr
+               { TyClD (mkTyData NewType (unLoc $2) [$4] Nothing) }
        | 'class' tycl_hdr fds
                { TyClD (mkClassDecl (unLoc $2) (unLoc $3) [] emptyBag) }
 

diff --git a/ghc/compiler/parser/RdrHsSyn.lhs b/ghc/compiler/parser/RdrHsSyn.lhs
index 656fc34..45b015b 100644 (file)
--- a/ghc/compiler/parser/RdrHsSyn.lhs
+++ b/ghc/compiler/parser/RdrHsSyn.lhs
@@ -51,7 +51,7 @@ module RdrHsSyn (
 import HsSyn           -- Lots of it
 import IfaceType
 import HscTypes                ( ModIface(..), emptyModIface, mkIfaceVerCache )
-import IfaceSyn                ( IfaceDecl(..), IfaceIdInfo(..) )
+import IfaceSyn                ( IfaceDecl(..), IfaceIdInfo(..), IfaceConDecl(..) )
 import RdrName         ( RdrName, isRdrTyVar, mkUnqual, rdrNameOcc, 
                          isRdrTyVar, isRdrDataCon, isUnqual, getRdrName, isQual,
                          setRdrNameSpace, rdrNameModule )
@@ -64,7 +64,7 @@ import ForeignCall    ( CCallConv, Safety, CCallTarget(..), CExportSpec(..),
                          DNCallSpec(..), DNKind(..))
 import OccName         ( OccName, srcDataName, varName, isDataOcc, isTcOcc, 
                          occNameUserString, isValOcc )
-import BasicTypes      ( initialVersion )
+import BasicTypes      ( initialVersion, StrictnessMark(..) )
 import TyCon           ( DataConDetails(..) )
 import Module          ( ModuleName )
 import SrcLoc
@@ -246,7 +246,8 @@ hsIfaceDecl (TyClD decl@(TyData {}))
                ifName = rdrNameOcc (tcdName decl), 
                ifTyVars = hsIfaceTvs (tcdTyVars decl), 
                ifCtxt = hsIfaceCtxt (unLoc (tcdCtxt decl)),
-               ifCons = Unknown, ifRec = NonRecursive,
+               ifCons = hsIfaceCons (tcdCons decl), 
+               ifRec = NonRecursive,
                ifVrcs = [], ifGeneric = False }
        -- I'm not sure that [] is right for ifVrcs, but
        -- since we don't use them I'm not going to fiddle
@@ -261,6 +262,35 @@ hsIfaceDecl (TyClD decl@(ClassDecl {}))
 
 hsIfaceDecl decl = pprPanic "hsIfaceDecl" (ppr decl)
 
+hsIfaceCons :: [LConDecl RdrName] -> DataConDetails IfaceConDecl
+hsIfaceCons cons
+  | null cons  -- data T a, meaning "constructors unspecified", not "no constructors"
+  = Unknown    
+  | otherwise  -- data T a = C1 | C2 
+  = DataCons (map (hsIfaceCon . unLoc) cons)
+
+hsIfaceCon :: ConDecl RdrName -> IfaceConDecl
+hsIfaceCon (ConDecl lname ex_tvs ex_ctxt details)
+  = IfaceConDecl (get_occ lname)
+                (hsIfaceTvs ex_tvs)
+                (hsIfaceCtxt (unLoc ex_ctxt))
+                (map (hsIfaceLType . getBangType       . unLoc) args)
+                (map (hsStrictMark . getBangStrictness . unLoc) args)
+                flds
+  where
+    (args, flds) = case details of
+                       PrefixCon args -> (args, [])
+                       InfixCon a1 a2 -> ([a1,a2], [])
+                       RecCon fs      -> (map snd fs, map (get_occ . fst) fs)
+    get_occ lname = rdrNameOcc (unLoc lname)
+
+hsStrictMark :: HsBang -> StrictnessMark
+-- Warning: in source files the {-# UNPACK #-} pragma (HsUnbox) is a request
+--         but in an hi-boot file it's interpreted as the Truth!
+hsStrictMark HsNoBang = NotMarkedStrict
+hsStrictMark HsStrict = MarkedStrict
+hsStrictMark HsUnbox  = MarkedUnboxed
+
 hsIfaceName rdr_name   -- Qualify unqualifed occurrences
                                -- with the module name
   | isUnqual rdr_name = LocalTop (rdrNameOcc rdr_name)

diff --git a/ghc/docs/users_guide/separate_compilation.sgml b/ghc/docs/users_guide/separate_compilation.sgml
index fe51108..262821e 100644 (file)
--- a/ghc/docs/users_guide/separate_compilation.sgml
+++ b/ghc/docs/users_guide/separate_compilation.sgml
@@ -948,6 +948,32 @@ newtype GHC.IOBase.IO a
          <literal>instances</literal> or derive them automatically.
 </para>
        </listitem>
+
+<listitem> <para>For <literal>data</literal> or <literal>newtype</literal> declaration, you may omit all
+the constructors, thus:
+<ProgramListing>
+module A where
+  data TA
+</ProgramListing>
+      (You must write all the type parameters, but omit the
+      '=' and everything that follows it.)  In a <emphasis>source</emphasis> program
+         this would declare TA to have no constructors (a GHC extension: see <xref linkend="nullary-types">),
+         but in an hi-boot file it means "I don't know or care what the construtors are".
+           This is the most common form of data type declaration, because it's easy to get right.</para>
+         <para>
+         You <emphasis>can</emphasis> also write out the constructors but, if you do so, you must write
+         it out precisely as in its real definition. 
+           It is especially delicate if you use a strictness annotation "!", 
+         with or without an <literal>{-# UNPACK #-}</literal> pragma.  In a source file
+         GHC may or may not choose to unbox the argument, but in an hi-boot file it's
+         assumed that you express the <emphasis>outcome</emphasis> of this decision.  
+           (So in the cases where GHC decided not to unpack, you must not use the pragma.)
+           Tread with care.</para>
+       </listitem>
+
+<listitem> <para>For <literal>class</literal> declaration, you may not specify any class
+operations.  We could lift this restriction if it became tiresome.</para>
+</listitem>
       </itemizedlist>
 
       <para>Notice that we only put the declaration for the newtype
@@ -955,18 +981,6 @@ newtype GHC.IOBase.IO a
       not the signature for <Function>f</Function>, since
       <Function>f</Function> isn't used by <literal>B</literal>.</para>
 
-      <para>If you want an <literal>hi-boot</literal> file to export a
-      data type, but you don't want to give its constructors (because
-      the constructors aren't used by the SOURCE-importing module),
-      you can write simply:</para>
-
-<ProgramListing>
-module A where
-data TA
-</ProgramListing>
-
-      <para>(You must write all the type parameters, but leave out the
-      '=' and everything that follows it.)</para>
     </sect2>