[project @ 1999-06-28 15:42:33 by simonmar]

Fix some pretty subtle bugs in the lexing of qualified names.

4 files changed, 34 insertions, 41 deletions

diff --git a/ghc/compiler/parser/Lex.lhs b/ghc/compiler/parser/Lex.lhs
index 25aa14c5f5..727039c7d8 100644
--- a/ghc/compiler/parser/Lex.lhs
+++ b/ghc/compiler/parser/Lex.lhs
@@ -96,15 +96,13 @@ Laziness, you know it makes sense :-)
 
 \begin{code}
 data Token
-  = ITas  			-- Haskell keywords
-  | ITcase
+  = ITcase  			-- Haskell keywords
   | ITclass
   | ITdata
   | ITdefault
   | ITderiving
   | ITdo
   | ITelse
-  | IThiding
   | ITif
   | ITimport
   | ITin
@@ -116,7 +114,6 @@ data Token
   | ITmodule
   | ITnewtype
   | ITof
-  | ITqualified
   | ITthen
   | ITtype
   | ITwhere
@@ -245,7 +242,6 @@ pragmaKeywordsFM = listToUFM $
 haskellKeywordsFM = listToUFM $
       map (\ (x,y) -> (_PK_ x,y))
        [( "_",		ITunderscore ),
-	( "as",		ITas ),
 	( "case",	ITcase ),     
 	( "class",	ITclass ),    
 	( "data",	ITdata ),     
@@ -253,7 +249,6 @@ haskellKeywordsFM = listToUFM $
 	( "deriving",	ITderiving ), 
 	( "do",		ITdo ),       
 	( "else",	ITelse ),     
-	( "hiding",	IThiding ),
 	( "if",		ITif ),       
 	( "import",	ITimport ),   
 	( "in",		ITin ),       
@@ -265,7 +260,6 @@ haskellKeywordsFM = listToUFM $
 	( "module",	ITmodule ),   
 	( "newtype",	ITnewtype ),  
 	( "of",		ITof ),       
-	( "qualified",	ITqualified ),
 	( "then",	ITthen ),     
 	( "type",	ITtype ),     
 	( "where",	ITwhere ),
@@ -341,6 +335,10 @@ haskellKeySymsFM = listToUFM $
        ,("!",		ITbang)
        ,(".",		ITdot)		-- sadly, for 'forall a . t'
        ]
+
+not_special_op ITminus = False
+not_special_op ITbang  = False
+not_special_op _ = True
 \end{code}
 
 -----------------------------------------------------------------------------
@@ -980,8 +978,9 @@ lex_id3 cont glaexts mod buf just_a_conid
        new_buf = mergeLexemes buf buf'
      in
      case lookupUFM haskellKeySymsFM lexeme of {
-	Just kwd_token -> just_a_conid;	-- avoid M.:: etc.
-	Nothing        -> cont (mk_qvar_token mod lexeme) new_buf
+	Just kwd_token | not_special_op kwd_token
+			-> just_a_conid;	-- avoid M.::, but not M.!
+	other -> cont (mk_qvar_token mod lexeme) new_buf
      }}
 
   | otherwise   =
@@ -1003,8 +1002,6 @@ lex_id3 cont glaexts mod buf just_a_conid
      case _scc_ "Lex.haskellKeyword" lookupUFM haskellKeywordsFM lexeme of {
     	    Just kwd_token -> just_a_conid; -- avoid M.where etc.
     	    Nothing        -> is_a_qvarid
-	-- TODO: special ids (as, qualified, hiding) shouldn't be
-	-- recognised as keywords here.  ie.  M.as is a qualified varid.
      }}}
 
 
diff --git a/ghc/compiler/parser/ParseUtil.lhs b/ghc/compiler/parser/ParseUtil.lhs
index ce4f71bfcf..2be5030193 100644
--- a/ghc/compiler/parser/ParseUtil.lhs
+++ b/ghc/compiler/parser/ParseUtil.lhs
@@ -14,6 +14,10 @@ module ParseUtil (
 	, mkRecConstrOrUpdate	-- HsExp -> [HsFieldUpdate] -> P HsExp
 	, groupBindings
 
+	, checkAs
+	, checkHiding
+	, checkQualified
+
 	, checkPrec 		-- String -> P String
 	, checkCallConv		-- FAST_STRING -> P CallConv
 	, checkContext		-- HsType -> P HsContext
@@ -33,10 +37,9 @@ module ParseUtil (
 	, funTyCon_RDR
 
 	-- pseudo-keywords, in var and tyvar forms (all :: RdrName)
-	, as_var_RDR, hiding_var_RDR, qualified_var_RDR, forall_var_RDR
+	, forall_var_RDR
 	, export_var_RDR, label_var_RDR, dynamic_var_RDR, unsafe_var_RDR
 
-	, as_tyvar_RDR, hiding_tyvar_RDR, qualified_tyvar_RDR
 	, export_tyvar_RDR, label_tyvar_RDR, dynamic_tyvar_RDR
 	, unsafe_tyvar_RDR
 
@@ -69,6 +72,9 @@ parseError s =
   getSrcLocP `thenP` \ loc ->
   failMsgP (hcat [ppr loc, text ": ", text s])
 
+parseErrorOnInput :: P a
+parseErrorOnInput buf PState{ loc = loc } = PFailed (srcParseErr buf loc)
+
 srcParseErr :: StringBuffer -> SrcLoc -> Message
 srcParseErr s l
   = hcat [ppr l, ptext SLIT(": parse error on input "),
@@ -77,6 +83,18 @@ srcParseErr s l
 cbot = panic "CCall:result_ty"
 
 -----------------------------------------------------------------------------
+-- Special Ids
+
+checkAs, checkQualified, checkHiding :: FAST_STRING -> P ()
+
+checkAs s 	 | s == SLIT("as") 	  = returnP ()
+ 	  	 | otherwise              = parseErrorOnInput
+checkQualified s | s == SLIT("qualified") = returnP ()
+ 		 | otherwise              = parseErrorOnInput
+checkHiding s  	 | s == SLIT("hiding")    = returnP ()
+ 		 | otherwise              = parseErrorOnInput
+
+-----------------------------------------------------------------------------
 -- splitForConApp
 
 -- When parsing data declarations, we sometimes inadvertently parse
@@ -428,27 +446,18 @@ unitName = SLIT("()")
 funName  = SLIT("(->)")
 listName = SLIT("[]")
 
-asName              = SLIT("as")
-hidingName          = SLIT("hiding")
-qualifiedName       = SLIT("qualified")
 forallName          = SLIT("forall")
 exportName	    = SLIT("export")
 labelName	    = SLIT("label")
 dynamicName	    = SLIT("dynamic")
 unsafeName          = SLIT("unsafe")
 
-as_var_RDR          = mkSrcUnqual varName asName
-hiding_var_RDR      = mkSrcUnqual varName hidingName
-qualified_var_RDR   = mkSrcUnqual varName qualifiedName
 forall_var_RDR      = mkSrcUnqual varName forallName
 export_var_RDR      = mkSrcUnqual varName exportName
 label_var_RDR       = mkSrcUnqual varName labelName
 dynamic_var_RDR     = mkSrcUnqual varName dynamicName
 unsafe_var_RDR      = mkSrcUnqual varName unsafeName
 
-as_tyvar_RDR        = mkSrcUnqual tvName asName
-hiding_tyvar_RDR    = mkSrcUnqual tvName hidingName
-qualified_tyvar_RDR = mkSrcUnqual tvName qualifiedName
 export_tyvar_RDR    = mkSrcUnqual tvName exportName
 label_tyvar_RDR     = mkSrcUnqual tvName labelName
 dynamic_tyvar_RDR   = mkSrcUnqual tvName dynamicName
diff --git a/ghc/compiler/parser/Parser.y b/ghc/compiler/parser/Parser.y
index 475534f139..f97ff966db 100644
--- a/ghc/compiler/parser/Parser.y
+++ b/ghc/compiler/parser/Parser.y
@@ -1,6 +1,6 @@
 {-
 -----------------------------------------------------------------------------
-$Id: Parser.y,v 1.7 1999/06/25 14:38:54 simonmar Exp $
+$Id: Parser.y,v 1.8 1999/06/28 15:42:33 simonmar Exp $
 
 Haskell grammar.
 
@@ -61,7 +61,6 @@ Conflicts: 14 shift/reduce
 
 %token
  '_'            { ITunderscore }		-- Haskell keywords
- 'as' 		{ ITas }
  'case' 	{ ITcase }  	
  'class' 	{ ITclass } 
  'data' 	{ ITdata } 
@@ -69,7 +68,6 @@ Conflicts: 14 shift/reduce
  'deriving' 	{ ITderiving }
  'do' 		{ ITdo }
  'else' 	{ ITelse }
- 'hiding' 	{ IThiding }
  'if' 		{ ITif }
  'import' 	{ ITimport }
  'in' 		{ ITin }
@@ -81,7 +79,6 @@ Conflicts: 14 shift/reduce
  'module' 	{ ITmodule }
  'newtype' 	{ ITnewtype }
  'of' 		{ ITof }
- 'qualified' 	{ ITqualified }
  'then' 	{ ITthen }
  'type' 	{ ITtype }
  'where' 	{ ITwhere }
@@ -860,9 +857,6 @@ qvarid :: { RdrName }
 
 varid :: { RdrName }
 	: VARID			{ mkSrcUnqual varName $1 }
-	| 'as'			{ as_var_RDR }
-	| 'qualified'		{ qualified_var_RDR }
-	| 'hiding'		{ hiding_var_RDR }
 	| 'forall'		{ forall_var_RDR }
 	| 'export'		{ export_var_RDR }
 	| 'label'		{ label_var_RDR }
@@ -871,14 +865,16 @@ varid :: { RdrName }
 
 varid_no_unsafe :: { RdrName }
 	: VARID			{ mkSrcUnqual varName $1 }
-	| 'as'			{ as_var_RDR }
-	| 'qualified'		{ qualified_var_RDR }
-	| 'hiding'		{ hiding_var_RDR }
 	| 'forall'		{ forall_var_RDR }
 	| 'export'		{ export_var_RDR }
 	| 'label'		{ label_var_RDR }
 	| 'dynamic'		{ dynamic_var_RDR }
 
+-- ``special'' Ids
+'as' 	    :: { () } : VARID	{% checkAs $1 }
+'qualified' :: { () } : VARID	{% checkQualified $1 }
+'hiding'    :: { () } : VARID	{% checkHiding $1 }
+
 -----------------------------------------------------------------------------
 -- ConIds
 
@@ -970,9 +966,6 @@ qtycls 	:: { RdrName }
 
 tyvar 	:: { RdrName }
 	: VARID			{ mkSrcUnqual tvName $1 }
-	| 'as'			{ as_tyvar_RDR }
-	| 'qualified'		{ qualified_tyvar_RDR }
-	| 'hiding'		{ hiding_tyvar_RDR }
 	| 'export'		{ export_var_RDR }
 	| 'label'		{ label_var_RDR }
 	| 'dynamic'		{ dynamic_var_RDR }
diff --git a/ghc/compiler/rename/ParseIface.y b/ghc/compiler/rename/ParseIface.y
index 5d58b407a6..419fa11947 100644
--- a/ghc/compiler/rename/ParseIface.y
+++ b/ghc/compiler/rename/ParseIface.y
@@ -69,9 +69,6 @@ import Ratio ( (%) )
  'then' 	{ ITthen }
  'type' 	{ ITtype }
  'where' 	{ ITwhere }
- 'as' 		{ ITas }
- 'qualified' 	{ ITqualified }
- 'hiding' 	{ IThiding }
 
  'forall'	{ ITforall }			-- GHC extension keywords
  'foreign'	{ ITforeign }
@@ -459,9 +456,6 @@ var_fs		:: { EncodedFS }
 		: VARID			{ $1 }
 		| VARSYM		{ $1 }
 		| '!'	  		{ SLIT("!") }
-		| 'as'			{ SLIT("as") }
-		| 'qualified'		{ SLIT("qualified") }
-		| 'hiding'		{ SLIT("hiding") }
 		| 'forall'		{ SLIT("forall") }
 		| 'foreign'		{ SLIT("foreign") }
 		| 'export'		{ SLIT("export") }