path: root/utils/genprimopcode/Main.hs

{-# OPTIONS -cpp #-}
------------------------------------------------------------------
-- A primop-table mangling program                              --
------------------------------------------------------------------

module Main where

import Parser
import Syntax

import Char
import List
import System ( getArgs )
import Maybe ( catMaybes )

main :: IO ()
main = getArgs >>= \args ->
       if length args /= 1 || head args `notElem` known_args
       then error ("usage: genprimopcode command < primops.txt > ...\n"
                   ++ "   where command is one of\n"
                   ++ unlines (map ("            "++) known_args)
                  )
       else
       do s <- getContents
          case parse s of
             Left err -> error ("parse error at " ++ (show err))
             Right p_o_specs@(Info _ entries)
                -> seq (sanityTop p_o_specs) (
                   case head args of

                      "--data-decl" 
                         -> putStr (gen_data_decl p_o_specs)

                      "--has-side-effects" 
                         -> putStr (gen_switch_from_attribs 
                                       "has_side_effects" 
                                       "primOpHasSideEffects" p_o_specs)

                      "--out-of-line" 
                         -> putStr (gen_switch_from_attribs 
                                       "out_of_line" 
                                       "primOpOutOfLine" p_o_specs)

                      "--commutable" 
                         -> putStr (gen_switch_from_attribs 
                                       "commutable" 
                                       "commutableOp" p_o_specs)

                      "--needs-wrapper" 
                         -> putStr (gen_switch_from_attribs 
                                       "needs_wrapper" 
                                       "primOpNeedsWrapper" p_o_specs)

                      "--can-fail" 
                         -> putStr (gen_switch_from_attribs 
                                       "can_fail" 
                                       "primOpCanFail" p_o_specs)

                      "--strictness" 
                         -> putStr (gen_switch_from_attribs 
                                       "strictness" 
                                       "primOpStrictness" p_o_specs)

                      "--primop-primop-info" 
                         -> putStr (gen_primop_info p_o_specs)

                      "--primop-tag" 
                         -> putStr (gen_primop_tag p_o_specs)

                      "--primop-list" 
                         -> putStr (gen_primop_list p_o_specs)

                      "--make-haskell-wrappers" 
                         -> putStr (gen_wrappers p_o_specs)
			
                      "--make-haskell-source" 
                         -> putStr (gen_hs_source p_o_specs)

                      "--make-ext-core-source"
                         -> putStr (gen_ext_core_source entries)

		      "--make-latex-doc"
			 -> putStr (gen_latex_doc p_o_specs)

                      _ -> error "Should not happen, known_args out of sync?"
                   )

known_args :: [String]
known_args 
   = [ "--data-decl",
       "--has-side-effects",
       "--out-of-line",
       "--commutable",
       "--needs-wrapper",
       "--can-fail",
       "--strictness",
       "--primop-primop-info",
       "--primop-tag",
       "--primop-list",
       "--make-haskell-wrappers",
       "--make-haskell-source",
       "--make-ext-core-source",
       "--make-latex-doc"
     ]

------------------------------------------------------------------
-- Code generators -----------------------------------------------
------------------------------------------------------------------

gen_hs_source :: Info -> String
gen_hs_source (Info defaults entries) =
       "{-\n"
    ++ "This is a generated file (generated by genprimopcode).\n"
    ++ "It is not code to actually be used. Its only purpose is to be\n"
    ++ "consumed by haddock.\n"
    ++ "-}\n"
    ++ "\n"
	++ "-----------------------------------------------------------------------------\n"
	++ "-- |\n"
	++ "-- Module      :  GHC.Prim\n"
	++ "-- \n"
	++ "-- Maintainer  :  cvs-ghc@haskell.org\n"
	++ "-- Stability   :  internal\n"
	++ "-- Portability :  non-portable (GHC extensions)\n"
	++ "--\n"
	++ "-- GHC\'s primitive types and operations.\n"
	++ "-- Use GHC.Exts from the base package instead of importing this\n"
	++ "-- module directly.\n"
	++ "--\n" 
	++ "-----------------------------------------------------------------------------\n"
	++ "module GHC.Prim (\n"
	++ unlines (map (("\t" ++) . hdr) entries)
	++ ") where\n"
    ++ "\n"
    ++ "import GHC.Types\n"
    ++ "\n"
    ++ "{-\n"
	++ unlines (map opt defaults)
    ++ "-}\n"
	++ unlines (concatMap ent entries) ++ "\n\n\n"
     where opt (OptionFalse n)	  = n ++ " = False"
           opt (OptionTrue n)	  = n ++ " = True"
	   opt (OptionString n v) = n ++ " = { " ++ v ++ "}"

	   hdr s@(Section {})			 = sec s
	   hdr (PrimOpSpec { name = n })	 = wrapOp n ++ ","
	   hdr (PseudoOpSpec { name = n })	 = wrapOp n ++ ","
	   hdr (PrimTypeSpec { ty = TyApp n _ }) = wrapTy n ++ ","
	   hdr (PrimTypeSpec {})                 = error "Illegal type spec"

	   ent   (Section {})	   = []
	   ent o@(PrimOpSpec {})   = spec o
	   ent o@(PrimTypeSpec {}) = spec o
	   ent o@(PseudoOpSpec {}) = spec o

	   sec s = "\n-- * " ++ escape (title s) ++ "\n"
			++ (unlines $ map ("-- " ++ ) $ lines $ unlatex $ escape $ "|" ++ desc s) ++ "\n"

	   spec o = comm : decls
	     where decls = case o of
			PrimOpSpec { name = n, ty = t }	  ->
                            [ wrapOp n ++ " :: " ++ pprTy t,
                              wrapOp n ++ " = let x = x in x" ]
			PseudoOpSpec { name = n, ty = t } ->
                            [ wrapOp n ++ " :: " ++ pprTy t,
                              wrapOp n ++ " = let x = x in x" ]
			PrimTypeSpec { ty = t }	  ->
                            [ "data " ++ pprTy t ]
			Section { } -> []

		   comm = case (desc o) of
		   	[] -> ""
			d -> "\n" ++ (unlines $ map ("-- " ++ ) $ lines $ unlatex $ escape $ "|" ++ d)

	   wrapOp nm | isAlpha (head nm) = nm
		     | otherwise	 = "(" ++ nm ++ ")"
	   wrapTy nm | isAlpha (head nm) = nm
		     | otherwise	 = "(" ++ nm ++ ")"
	   unlatex s = case s of
	   	'\\':'t':'e':'x':'t':'t':'t':'{':cs -> markup "@" "@" cs
		'{':'\\':'t':'t':cs -> markup "@" "@" cs
		'{':'\\':'i':'t':cs -> markup "/" "/" cs
		c : cs -> c : unlatex cs
		[] -> []
	   markup s t xs = s ++ mk (dropWhile isSpace xs)
	   	where mk ""	   = t
	              mk ('\n':cs) = ' ' : mk cs
	              mk ('}':cs)  = t ++ unlatex cs
	              mk (c:cs)	   = c : mk cs
	   escape = concatMap (\c -> if c `elem` special then '\\':c:[] else c:[])
	   	where special = "/'`\"@<"

pprTy :: Ty -> String
pprTy = pty
    where
          pty (TyF t1 t2) = pbty t1 ++ " -> " ++ pty t2
          pty t      = pbty t
          pbty (TyApp tc ts) = tc ++ concat (map (' ' :) (map paty ts))
          pbty (TyUTup ts)   = "(# "
                            ++ concat (intersperse "," (map pty ts))
                            ++ " #)"
          pbty t             = paty t

          paty (TyVar tv)    = tv
          paty t             = "(" ++ pty t ++ ")"
--
-- Generates the type environment that the stand-alone External Core tools use.
gen_ext_core_source :: [Entry] -> String
gen_ext_core_source entries =
      "-----------------------------------------------------------------------\n"
   ++ "-- This module is automatically generated by the GHC utility\n"
   ++ "-- \"genprimopcode\". Do not edit!\n"
   ++ "-----------------------------------------------------------------------\n"
   ++ "module Language.Core.PrimEnv(primTcs, primVals, intLitTypes, ratLitTypes,"
   ++ "\n charLitTypes, stringLitTypes) where\nimport Language.Core.Core"
   ++ "\nimport Language.Core.Encoding\n\n"
   ++ "primTcs :: [(Tcon, Kind)]\n"
   ++ "primTcs = [\n"
   ++ printList tcEnt entries 
   ++ "   ]\n"
   ++ "primVals :: [(Var, Ty)]\n"
   ++ "primVals = [\n"
   ++ printList valEnt entries
   ++ "]\n"
   ++ "intLitTypes :: [Ty]\n"
   ++ "intLitTypes = [\n"
   ++ printList tyEnt (intLitTys entries)
   ++ "]\n"
   ++ "ratLitTypes :: [Ty]\n"
   ++ "ratLitTypes = [\n"
   ++ printList tyEnt (ratLitTys entries)
   ++ "]\n"
   ++ "charLitTypes :: [Ty]\n"
   ++ "charLitTypes = [\n"
   ++ printList tyEnt (charLitTys entries)
   ++ "]\n"
   ++ "stringLitTypes :: [Ty]\n"
   ++ "stringLitTypes = [\n"
   ++ printList tyEnt (stringLitTys entries)
   ++ "]\n\n"

  where printList f = concat . intersperse ",\n" . filter (not . null) . map f   
        tcEnt  (PrimTypeSpec {ty=t}) = 
           case t of
            TyApp tc args -> parens tc (tcKind tc args)
            _             -> error ("tcEnt: type in PrimTypeSpec is not a type"
                              ++ " constructor: " ++ show t)  
        tcEnt  _                = ""
        -- hack alert!
        -- The primops.txt.pp format doesn't have enough information in it to 
        -- print out some of the information that ext-core needs (like kinds,
        -- and later on in this code, module names) so we special-case. An
        -- alternative would be to refer to things indirectly and hard-wire
        -- certain things (e.g., the kind of the Any constructor, here) into
        -- ext-core's Prims module again.
        tcKind "Any" _                = "Klifted"
        tcKind tc [] | last tc == '#' = "Kunlifted"
        tcKind _  [] | otherwise      = "Klifted"
        -- assumes that all type arguments are lifted (are they?)
        tcKind tc (_v:as)              = "(Karrow Klifted " ++ tcKind tc as
                                         ++ ")"
        valEnt (PseudoOpSpec {name=n, ty=t}) = valEntry n t
        valEnt (PrimOpSpec {name=n, ty=t})   = valEntry n t
        valEnt _                             = ""
        valEntry name' ty' = parens name' (mkForallTy (freeTvars ty') (pty ty'))
            where pty (TyF t1 t2) = mkFunTy (pty t1) (pty t2)
                  pty (TyApp tc ts) = mkTconApp (mkTcon tc) (map pty ts)  
                  pty (TyUTup ts)   = mkUtupleTy (map pty ts)
                  pty (TyVar tv)    = paren $ "Tvar \"" ++ tv ++ "\""

                  mkFunTy s1 s2 = "Tapp " ++ (paren ("Tapp (Tcon tcArrow)" 
                                               ++ " " ++ paren s1))
                                          ++ " " ++ paren s2
                  mkTconApp tc args = foldl tapp tc args
                  mkTcon tc = paren $ "Tcon " ++ paren (qualify True tc)
                  mkUtupleTy args = foldl tapp (tcUTuple (length args)) args   
                  mkForallTy [] t = t
                  mkForallTy vs t = foldr 
                     (\ v s -> "Tforall " ++ 
                               (paren (quote v ++ ", " ++ vKind v)) ++ " "
                               ++ paren s) t vs

                  -- hack alert!
                  vKind "o" = "Kopen"
                  vKind _   = "Klifted"

                  freeTvars (TyF t1 t2)   = freeTvars t1 `union` freeTvars t2
                  freeTvars (TyApp _ tys) = freeTvarss tys
                  freeTvars (TyVar v)     = [v]
                  freeTvars (TyUTup tys)  = freeTvarss tys
                  freeTvarss = nub . concatMap freeTvars

                  tapp s nextArg = paren $ "Tapp " ++ s ++ " " ++ paren nextArg
                  tcUTuple n = paren $ "Tcon " ++ paren (qualify False $ "Z" 
                                                          ++ show n ++ "H")

        tyEnt (PrimTypeSpec {ty=(TyApp tc _args)}) = "   " ++ paren ("Tcon " ++
                                                       (paren (qualify True tc)))
        tyEnt _ = ""

        -- more hacks. might be better to do this on the ext-core side,
        -- as per earlier comment
        qualify _ tc | tc == "Bool" = "Just boolMname" ++ ", " 
                                                ++ ze True tc
        qualify _ tc | tc == "()"  = "Just baseMname" ++ ", "
                                                ++ ze True tc
        qualify enc tc = "Just primMname" ++ ", " ++ (ze enc tc)
        ze enc tc      = (if enc then "zEncodeString " else "")
                                      ++ "\"" ++ tc ++ "\""

        intLitTys = prefixes ["Int", "Word", "Addr", "Char"]
        ratLitTys = prefixes ["Float", "Double"]
        charLitTys = prefixes ["Char"]
        stringLitTys = prefixes ["Addr"]
        prefixes ps = filter (\ t ->
                        case t of
                          (PrimTypeSpec {ty=(TyApp tc _args)}) ->
                            any (\ p -> p `isPrefixOf` tc) ps
                          _ -> False)

        parens n ty' = "      (zEncodeString \"" ++ n ++ "\", " ++ ty' ++ ")"
        paren s = "(" ++ s ++ ")"
        quote s = "\"" ++ s ++ "\""

gen_latex_doc :: Info -> String
gen_latex_doc (Info defaults entries)
   = "\\primopdefaults{" 
	 ++ mk_options defaults
	 ++ "}\n"
     ++ (concat (map mk_entry entries))
     where mk_entry (PrimOpSpec {cons=constr,name=n,ty=t,cat=c,desc=d,opts=o}) =
   		 "\\primopdesc{" 
		 ++ latex_encode constr ++ "}{"
		 ++ latex_encode n ++ "}{"
		 ++ latex_encode (zencode n) ++ "}{"
		 ++ latex_encode (show c) ++ "}{"
		 ++ latex_encode (mk_source_ty t) ++ "}{"
		 ++ latex_encode (mk_core_ty t) ++ "}{"
		 ++ d ++ "}{"
		 ++ mk_options o
		 ++ "}\n"
           mk_entry (Section {title=ti,desc=d}) =
		 "\\primopsection{" 
		 ++ latex_encode ti ++ "}{"
		 ++ d ++ "}\n"
           mk_entry (PrimTypeSpec {ty=t,desc=d,opts=o}) =
   		 "\\primtypespec{"
		 ++ latex_encode (mk_source_ty t) ++ "}{"
		 ++ latex_encode (mk_core_ty t) ++ "}{"
		 ++ d ++ "}{"
		 ++ mk_options o
		 ++ "}\n"
           mk_entry (PseudoOpSpec {name=n,ty=t,desc=d,opts=o}) =
		 "\\pseudoopspec{"
		 ++ latex_encode (zencode n) ++ "}{"
		 ++ latex_encode (mk_source_ty t) ++ "}{"
		 ++ latex_encode (mk_core_ty t) ++ "}{"
		 ++ d ++ "}{"
		 ++ mk_options o
		 ++ "}\n"
	   mk_source_ty typ = pty typ
	     where pty (TyF t1 t2) = pbty t1 ++ " -> " ++ pty t2
		   pty t = pbty t
		   pbty (TyApp tc ts) = tc ++ (concat (map (' ':) (map paty ts)))
		   pbty (TyUTup ts) = "(# " ++ (concat (intersperse "," (map pty ts))) ++ " #)"
		   pbty t = paty t
		   paty (TyVar tv) = tv
		   paty t = "(" ++ pty t ++ ")"
	   
	   mk_core_ty typ = foralls ++ (pty typ)
	     where pty (TyF t1 t2) = pbty t1 ++ " -> " ++ pty t2
		   pty t = pbty t
		   pbty (TyApp tc ts) = (zencode tc) ++ (concat (map (' ':) (map paty ts)))
		   pbty (TyUTup ts) = (zencode (utuplenm (length ts))) ++ (concat ((map (' ':) (map paty ts))))
		   pbty t = paty t
		   paty (TyVar tv) = zencode tv
		   paty (TyApp tc []) = zencode tc
		   paty t = "(" ++ pty t ++ ")"
		   utuplenm 1 = "(# #)"
		   utuplenm n = "(#" ++ (replicate (n-1) ',') ++ "#)"
		   foralls = if tvars == [] then "" else "%forall " ++ (tbinds tvars)
		   tvars = tvars_of typ
		   tbinds [] = ". " 
		   tbinds ("o":tbs) = "(o::?) " ++ (tbinds tbs)
		   tbinds (tv:tbs) = tv ++ " " ++ (tbinds tbs)
	   tvars_of (TyF t1 t2) = tvars_of t1 `union` tvars_of t2
	   tvars_of (TyApp _ ts) = foldl union [] (map tvars_of ts)
	   tvars_of (TyUTup ts) = foldr union [] (map tvars_of ts)
	   tvars_of (TyVar tv) = [tv]
	   
           mk_options o =
	     "\\primoptions{"
	      ++ mk_has_side_effects o ++ "}{"
	      ++ mk_out_of_line o ++ "}{"
	      ++ mk_commutable o ++ "}{"
 	      ++ mk_needs_wrapper o ++ "}{"
	      ++ mk_can_fail o ++ "}{"
	      ++ latex_encode (mk_strictness o) ++ "}{"
	      ++ "}"

  	   mk_has_side_effects o = mk_bool_opt o "has_side_effects" "Has side effects." "Has no side effects."
	   mk_out_of_line o = mk_bool_opt o "out_of_line" "Implemented out of line." "Implemented in line."
  	   mk_commutable o = mk_bool_opt o "commutable" "Commutable." "Not commutable."
  	   mk_needs_wrapper o = mk_bool_opt o "needs_wrapper" "Needs wrapper." "Needs no wrapper."
	   mk_can_fail o = mk_bool_opt o "can_fail" "Can fail." "Cannot fail."

	   mk_bool_opt o opt_name if_true if_false =
	     case lookup_attrib opt_name o of
	       Just (OptionTrue _) -> if_true
	       Just (OptionFalse _) -> if_false
	       Just (OptionString _ _) -> error "String value for boolean option"
	       Nothing -> ""
	   
	   mk_strictness o = 
	     case lookup_attrib "strictness" o of
	       Just (OptionString _ s) -> s  -- for now
	       Just _ -> error "Boolean value for strictness"
	       Nothing -> "" 

	   zencode xs =
	     case maybe_tuple xs of
		Just n  -> n		-- Tuples go to Z2T etc
		Nothing -> concat (map encode_ch xs)
	     where
	       maybe_tuple "(# #)" = Just("Z1H")
	       maybe_tuple ('(' : '#' : cs) = case count_commas (0::Int) cs of
						(n, '#' : ')' : _) -> Just ('Z' : shows (n+1) "H")
						_		   -> Nothing
	       maybe_tuple "()" = Just("Z0T")
	       maybe_tuple ('(' : cs)       = case count_commas (0::Int) cs of
						(n, ')' : _) -> Just ('Z' : shows (n+1) "T")
						_	     -> Nothing
	       maybe_tuple _    	     = Nothing
	       
	       count_commas :: Int -> String -> (Int, String)
	       count_commas n (',' : cs) = count_commas (n+1) cs
	       count_commas n cs	  = (n,cs)
	       
	       unencodedChar :: Char -> Bool	-- True for chars that don't need encoding
	       unencodedChar 'Z' = False
	       unencodedChar 'z' = False
	       unencodedChar c   = isAlphaNum c
	       
	       encode_ch :: Char -> String
	       encode_ch c | unencodedChar c = [c]	-- Common case first
	       
	       -- Constructors
	       encode_ch '('  = "ZL"	-- Needed for things like (,), and (->)
	       encode_ch ')'  = "ZR"	-- For symmetry with (
	       encode_ch '['  = "ZM"
	       encode_ch ']'  = "ZN"
	       encode_ch ':'  = "ZC"
	       encode_ch 'Z'  = "ZZ"
	       
	       -- Variables
	       encode_ch 'z'  = "zz"
	       encode_ch '&'  = "za"
	       encode_ch '|'  = "zb"
	       encode_ch '^'  = "zc"
	       encode_ch '$'  = "zd"
	       encode_ch '='  = "ze"
	       encode_ch '>'  = "zg"
	       encode_ch '#'  = "zh"
	       encode_ch '.'  = "zi"
	       encode_ch '<'  = "zl"
	       encode_ch '-'  = "zm"
	       encode_ch '!'  = "zn"
	       encode_ch '+'  = "zp"
	       encode_ch '\'' = "zq"
	       encode_ch '\\' = "zr"
	       encode_ch '/'  = "zs"
	       encode_ch '*'  = "zt"
	       encode_ch '_'  = "zu"
	       encode_ch '%'  = "zv"
	       encode_ch c    = 'z' : shows (ord c) "U"
		       
	   latex_encode [] = []
	   latex_encode (c:cs) | c `elem` "#$%&_^{}" = "\\" ++ c:(latex_encode cs)
	   latex_encode ('~':cs) = "\\verb!~!" ++ (latex_encode cs)
	   latex_encode ('\\':cs) = "$\\backslash$" ++ (latex_encode cs)
	   latex_encode (c:cs) = c:(latex_encode cs)

gen_wrappers :: Info -> String
gen_wrappers (Info _ entries)
   = "{-# LANGUAGE NoImplicitPrelude, UnboxedTuples #-}\n"
	-- Dependencies on Prelude must be explicit in libraries/base, but we
	-- don't need the Prelude here so we add NoImplicitPrelude.
     ++ "module GHC.PrimopWrappers where\n" 
     ++ "import qualified GHC.Prim\n" 
     ++ "import GHC.Types (Bool)\n"
     ++ "import GHC.Unit ()\n"
     ++ "import GHC.Prim (" ++ types ++ ")\n"
     ++ unlines (concatMap f specs)
     where
        specs = filter (not.dodgy) (filter is_primop entries)
        tycons = foldr union [] $ map (tyconsIn . ty) specs
        tycons' = filter (`notElem` ["()", "Bool"]) tycons
        types = concat $ intersperse ", " tycons'
        f spec = let args = map (\n -> "a" ++ show n) [1 .. arity (ty spec)]
                     src_name = wrap (name spec)
                     lhs = src_name ++ " " ++ unwords args
                     rhs = "(GHC.Prim." ++ name spec ++ ") " ++ unwords args
                 in ["{-# NOINLINE " ++ src_name ++ " #-}",
                     src_name ++ " :: " ++ pprTy (ty spec),
                     lhs ++ " = " ++ rhs]
        wrap nm | isLower (head nm) = nm
                | otherwise = "(" ++ nm ++ ")"

        dodgy spec
           = name spec `elem` 
             [-- C code generator can't handle these
              "seq#", 
              "tagToEnum#",
              -- not interested in parallel support
              "par#", "parGlobal#", "parLocal#", "parAt#", 
              "parAtAbs#", "parAtRel#", "parAtForNow#" 
             ]

gen_primop_list :: Info -> String
gen_primop_list (Info _ entries)
   = unlines (
        [      "   [" ++ cons first       ]
        ++
        map (\p -> "   , " ++ cons p) rest
        ++ 
        [     "   ]"     ]
     ) where (first:rest) = filter is_primop entries

gen_primop_tag :: Info -> String
gen_primop_tag (Info _ entries)
   = unlines (max_def_type : max_def :
              tagOf_type : zipWith f primop_entries [1 :: Int ..])
     where
        primop_entries = filter is_primop entries
        tagOf_type = "tagOf_PrimOp :: PrimOp -> FastInt"
        f i n = "tagOf_PrimOp " ++ cons i ++ " = _ILIT(" ++ show n ++ ")"
        max_def_type = "maxPrimOpTag :: Int"
        max_def      = "maxPrimOpTag = " ++ show (length primop_entries)

gen_data_decl :: Info -> String
gen_data_decl (Info _ entries)
   = let conss = map cons (filter is_primop entries)
     in  "data PrimOp\n   = " ++ head conss ++ "\n"
         ++ unlines (map ("   | "++) (tail conss))

gen_switch_from_attribs :: String -> String -> Info -> String
gen_switch_from_attribs attrib_name fn_name (Info defaults entries)
   = let defv = lookup_attrib attrib_name defaults
         alternatives = catMaybes (map mkAlt (filter is_primop entries))

         getAltRhs (OptionFalse _)    = "False"
         getAltRhs (OptionTrue _)     = "True"
         getAltRhs (OptionString _ s) = s

         mkAlt po
            = case lookup_attrib attrib_name (opts po) of
                 Nothing -> Nothing
                 Just xx -> Just (fn_name ++ " " ++ cons po ++ " = " ++ getAltRhs xx)

     in
         case defv of
            Nothing -> error ("gen_switch_from: " ++ attrib_name)
            Just xx 
               -> unlines alternatives
                  ++ fn_name ++ " _ = " ++ getAltRhs xx ++ "\n"

------------------------------------------------------------------
-- Create PrimOpInfo text from PrimOpSpecs -----------------------
------------------------------------------------------------------

gen_primop_info :: Info -> String
gen_primop_info (Info _ entries)
   = unlines (map mkPOItext (filter is_primop entries))

mkPOItext :: Entry -> String
mkPOItext i = mkPOI_LHS_text i ++ mkPOI_RHS_text i

mkPOI_LHS_text :: Entry -> String
mkPOI_LHS_text i
   = "primOpInfo " ++ cons i ++ " = "

mkPOI_RHS_text :: Entry -> String
mkPOI_RHS_text i
   = case cat i of
        Compare 
           -> case ty i of
                 TyF t1 (TyF _ _) 
                    -> "mkCompare " ++ sl_name i ++ ppType t1
                 _ -> error "Type error in comparison op"
        Monadic
           -> case ty i of
                 TyF t1 _
                    -> "mkMonadic " ++ sl_name i ++ ppType t1
                 _ -> error "Type error in monadic op"
        Dyadic
           -> case ty i of
                 TyF t1 (TyF _ _)
                    -> "mkDyadic " ++ sl_name i ++ ppType t1
                 _ -> error "Type error in dyadic op"
        GenPrimOp
           -> let (argTys, resTy) = flatTys (ty i)
                  tvs = nub (tvsIn (ty i))
              in
                  "mkGenPrimOp " ++ sl_name i ++ " " 
                      ++ listify (map ppTyVar tvs) ++ " "
                      ++ listify (map ppType argTys) ++ " "
                      ++ "(" ++ ppType resTy ++ ")"

sl_name :: Entry -> String
sl_name i = "(fsLit \"" ++ name i ++ "\") "

ppTyVar :: String -> String
ppTyVar "a" = "alphaTyVar"
ppTyVar "b" = "betaTyVar"
ppTyVar "c" = "gammaTyVar"
ppTyVar "s" = "deltaTyVar"
ppTyVar "o" = "openAlphaTyVar"
ppTyVar _   = error "Unknown type var"

ppType :: Ty -> String
ppType (TyApp "Bool"        []) = "boolTy"

ppType (TyApp "Int#"        []) = "intPrimTy"
ppType (TyApp "Int32#"      []) = "int32PrimTy"
ppType (TyApp "Int64#"      []) = "int64PrimTy"
ppType (TyApp "Char#"       []) = "charPrimTy"
ppType (TyApp "Word#"       []) = "wordPrimTy"
ppType (TyApp "Word32#"     []) = "word32PrimTy"
ppType (TyApp "Word64#"     []) = "word64PrimTy"
ppType (TyApp "Addr#"       []) = "addrPrimTy"
ppType (TyApp "Float#"      []) = "floatPrimTy"
ppType (TyApp "Double#"     []) = "doublePrimTy"
ppType (TyApp "ByteArray#"  []) = "byteArrayPrimTy"
ppType (TyApp "RealWorld"   []) = "realWorldTy"
ppType (TyApp "ThreadId#"   []) = "threadIdPrimTy"
ppType (TyApp "ForeignObj#" []) = "foreignObjPrimTy"
ppType (TyApp "BCO#"        []) = "bcoPrimTy"
ppType (TyApp "()"          []) = "unitTy" 	-- unitTy is TysWiredIn's name for ()

ppType (TyVar "a")               = "alphaTy"
ppType (TyVar "b")               = "betaTy"
ppType (TyVar "c")               = "gammaTy"
ppType (TyVar "s")               = "deltaTy"
ppType (TyVar "o")               = "openAlphaTy"
ppType (TyApp "State#" [x])      = "mkStatePrimTy " ++ ppType x
ppType (TyApp "MutVar#" [x,y])   = "mkMutVarPrimTy " ++ ppType x 
                                   ++ " " ++ ppType y
ppType (TyApp "MutableArray#" [x,y]) = "mkMutableArrayPrimTy " ++ ppType x
                                    ++ " " ++ ppType y

ppType (TyApp "MutableByteArray#" [x]) = "mkMutableByteArrayPrimTy " 
                                   ++ ppType x

ppType (TyApp "Array#" [x])      = "mkArrayPrimTy " ++ ppType x


ppType (TyApp "Weak#"  [x])      = "mkWeakPrimTy " ++ ppType x
ppType (TyApp "StablePtr#"  [x])      = "mkStablePtrPrimTy " ++ ppType x
ppType (TyApp "StableName#"  [x])      = "mkStableNamePrimTy " ++ ppType x

ppType (TyApp "MVar#" [x,y])     = "mkMVarPrimTy " ++ ppType x 
                                   ++ " " ++ ppType y
ppType (TyApp "TVar#" [x,y])     = "mkTVarPrimTy " ++ ppType x 
                                   ++ " " ++ ppType y
ppType (TyUTup ts)               = "(mkTupleTy Unboxed " 
                                   ++ listify (map ppType ts) ++ ")"

ppType (TyF s d) = "(mkFunTy (" ++ ppType s ++ ") (" ++ ppType d ++ "))"

ppType other
   = error ("ppType: can't handle: " ++ show other ++ "\n")

listify :: [String] -> String
listify ss = "[" ++ concat (intersperse ", " ss) ++ "]"

flatTys :: Ty -> ([Ty],Ty)
flatTys (TyF t1 t2) = case flatTys t2 of (ts,t) -> (t1:ts,t)
flatTys other       = ([],other)

tvsIn :: Ty -> [TyVar]
tvsIn (TyF t1 t2)    = tvsIn t1 ++ tvsIn t2
tvsIn (TyApp _ tys)  = concatMap tvsIn tys
tvsIn (TyVar tv)     = [tv]
tvsIn (TyUTup tys)   = concatMap tvsIn tys

tyconsIn :: Ty -> [TyCon]
tyconsIn (TyF t1 t2)    = tyconsIn t1 `union` tyconsIn t2
tyconsIn (TyApp tc tys) = foldr union [tc] $ map tyconsIn tys
tyconsIn (TyVar _)      = []
tyconsIn (TyUTup tys)   = foldr union [] $ map tyconsIn tys

arity :: Ty -> Int
arity = length . fst . flatTys