gf-3.1.6: src/compiler/GF/Compile/PGFtoHaskell.hs
----------------------------------------------------------------------
-- |
-- Module : PGFtoHaskell
-- Maintainer : Aarne Ranta
-- Stability : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/06/17 12:39:07 $
-- > CVS $Author: bringert $
-- > CVS $Revision: 1.8 $
--
-- to write a GF abstract grammar into a Haskell module with translations from
-- data objects into GF trees. Example: GSyntax for Agda.
-- AR 11/11/1999 -- 7/12/2000 -- 18/5/2004
-----------------------------------------------------------------------------
module GF.Compile.PGFtoHaskell (grammar2haskell) where
import PGF.CId
import PGF.Data
import PGF.Macros
import GF.Data.Operations
import GF.Infra.Option
import Data.List --(isPrefixOf, find, intersperse)
import qualified Data.Map as Map
type Prefix = String -> String
-- | the main function
grammar2haskell :: Options
-> String -- ^ Module name.
-> PGF
-> String
grammar2haskell opts name gr = foldr (++++) [] $
pragmas ++ haskPreamble name ++ [types, gfinstances gId lexical gr']
where gr' = hSkeleton gr
gadt = haskellOption opts HaskellGADT
lexical cat = haskellOption opts HaskellLexical && isLexicalCat opts cat
gId | haskellOption opts HaskellNoPrefix = id
| otherwise = ("G"++)
pragmas | gadt = ["{-# OPTIONS_GHC -fglasgow-exts #-}"]
| otherwise = []
types | gadt = datatypesGADT gId lexical gr'
| otherwise = datatypes gId lexical gr'
haskPreamble name =
[
"module " ++ name ++ " where",
"",
"import PGF",
"----------------------------------------------------",
"-- automatic translation from GF to Haskell",
"----------------------------------------------------",
"",
"class Gf a where",
" gf :: a -> Tree",
" fg :: Tree -> a",
"",
predefInst "GString" "String" "unStr" "mkStr",
"",
predefInst "GInt" "Int" "unInt" "mkInt",
"",
predefInst "GFloat" "Double" "unDouble" "mkDouble",
"",
"----------------------------------------------------",
"-- below this line machine-generated",
"----------------------------------------------------",
""
]
predefInst gtyp typ destr consr =
"newtype" +++ gtyp +++ "=" +++ gtyp +++ typ +++ " deriving Show" +++++
"instance Gf" +++ gtyp +++ "where" ++++
" gf (" ++ gtyp +++ "x) =" +++ consr +++ "x" ++++
" fg t =" ++++
" case "++destr++" t of" ++++
" Just x -> " +++ gtyp +++ "x" ++++
" Nothing -> error (\"no" +++ gtyp +++ "\" ++ show t)"
type OIdent = String
type HSkeleton = [(OIdent, [(OIdent, [OIdent])])]
datatypes :: Prefix -> (OIdent -> Bool) -> (String,HSkeleton) -> String
datatypes gId lexical = (foldr (+++++) "") . (filter (/="")) . (map (hDatatype gId lexical)) . snd
gfinstances :: Prefix -> (OIdent -> Bool) -> (String,HSkeleton) -> String
gfinstances gId lexical (m,g) = (foldr (+++++) "") $ (filter (/="")) $ (map (gfInstance gId lexical m)) g
hDatatype :: Prefix -> (OIdent -> Bool) -> (OIdent, [(OIdent, [OIdent])]) -> String
hDatatype _ _ ("Cn",_) = "" ---
hDatatype _ _ (cat,[]) = ""
hDatatype gId _ (cat,rules) | isListCat (cat,rules) =
"newtype" +++ gId cat +++ "=" +++ gId cat +++ "[" ++ gId (elemCat cat) ++ "]"
+++ "deriving Show"
hDatatype gId lexical (cat,rules) =
"data" +++ gId cat +++ "=" ++
(if length rules == 1 then "" else "\n ") +++
foldr1 (\x y -> x ++ "\n |" +++ y) constructors ++++
" deriving Show"
where
constructors = [gId f +++ foldr (+++) "" (map (gId) xx) | (f,xx) <- nonLexicalRules (lexical cat) rules]
++ if lexical cat then [lexicalConstructor cat +++ "String"] else []
nonLexicalRules :: Bool -> [(OIdent, [OIdent])] -> [(OIdent, [OIdent])]
nonLexicalRules False rules = rules
nonLexicalRules True rules = [r | r@(f,t) <- rules, not (null t)]
lexicalConstructor :: OIdent -> String
lexicalConstructor cat = "Lex" ++ cat
-- GADT version of data types
datatypesGADT :: Prefix -> (OIdent -> Bool) -> (String,HSkeleton) -> String
datatypesGADT gId lexical (_,skel) =
unlines (concatMap (hCatTypeGADT gId) skel)
+++++
"data Tree :: * -> * where" ++++ unlines (concatMap (map (" "++) . hDatatypeGADT gId lexical) skel)
hCatTypeGADT :: Prefix -> (OIdent, [(OIdent, [OIdent])]) -> [String]
hCatTypeGADT gId (cat,rules)
= ["type"+++gId cat+++"="+++"Tree"+++gId cat++"_",
"data"+++gId cat++"_"]
hDatatypeGADT :: Prefix -> (OIdent -> Bool) -> (OIdent, [(OIdent, [OIdent])]) -> [String]
hDatatypeGADT gId lexical (cat, rules)
| isListCat (cat,rules) = [gId cat+++"::"+++"["++gId (elemCat cat)++"]" +++ "->" +++ t]
| otherwise =
[ gId f +++ "::" +++ concatMap (\a -> gId a +++ "-> ") args ++ t
| (f,args) <- nonLexicalRules (lexical cat) rules ]
++ if lexical cat then [lexicalConstructor cat +++ ":: String ->"+++ t] else []
where t = "Tree" +++ gId cat ++ "_"
gfInstance :: Prefix -> (OIdent -> Bool) -> String -> (OIdent, [(OIdent, [OIdent])]) -> String
gfInstance gId lexical m crs = hInstance gId lexical m crs ++++ fInstance gId lexical m crs
----hInstance m ("Cn",_) = "" --- seems to belong to an old applic. AR 18/5/2004
hInstance _ _ m (cat,[]) = ""
hInstance gId lexical m (cat,rules)
| isListCat (cat,rules) =
"instance Gf" +++ gId cat +++ "where" ++++
" gf (" ++ gId cat +++ "[" ++ concat (intersperse "," baseVars) ++ "])"
+++ "=" +++ mkRHS ("Base"++ec) baseVars ++++
" gf (" ++ gId cat +++ "(x:xs)) = "
++ mkRHS ("Cons"++ec) ["x",prParenth (gId cat+++"xs")]
-- no show for GADTs
-- ++++ " gf (" ++ gId cat +++ "xs) = error (\"Bad " ++ cat ++ " value: \" ++ show xs)"
| otherwise =
"instance Gf" +++ gId cat +++ "where\n" ++
unlines ([mkInst f xx | (f,xx) <- nonLexicalRules (lexical cat) rules]
++ if lexical cat then [" gf (" ++ lexicalConstructor cat +++ "x) = mkApp (mkCId x) []"] else [])
where
ec = elemCat cat
baseVars = mkVars (baseSize (cat,rules))
mkInst f xx = let xx' = mkVars (length xx) in " gf " ++
(if length xx == 0 then gId f else prParenth (gId f +++ foldr1 (+++) xx')) +++
"=" +++ mkRHS f xx'
mkVars n = ["x" ++ show i | i <- [1..n]]
mkRHS f vars = "mkApp (mkCId \"" ++ f ++ "\")" +++
"[" ++ prTList ", " ["gf" +++ x | x <- vars] ++ "]"
----fInstance m ("Cn",_) = "" ---
fInstance _ _ m (cat,[]) = ""
fInstance gId lexical m (cat,rules) =
" fg t =" ++++
" case unApp t of" ++++
unlines [mkInst f xx | (f,xx) <- nonLexicalRules (lexical cat) rules] ++++
(if lexical cat then " (i,[]) -> " ++ lexicalConstructor cat +++ "(prCId i)" else "") ++++
" _ -> error (\"no" +++ cat ++ " \" ++ show t)"
where
mkInst f xx =
" Just (i," ++
"[" ++ prTList "," xx' ++ "])" +++
"| i == mkCId \"" ++ f ++ "\" ->" +++ mkRHS f xx'
where xx' = ["x" ++ show i | (_,i) <- zip xx [1..]]
mkRHS f vars
| isListCat (cat,rules) =
if "Base" `isPrefixOf` f then
gId cat +++ "[" ++ prTList ", " [ "fg" +++ x | x <- vars ] ++ "]"
else
let (i,t) = (init vars,last vars)
in "let" +++ gId cat +++ "xs = fg " ++ t +++ "in" +++
gId cat +++ prParenth (prTList ":" (["fg"+++v | v <- i] ++ ["xs"]))
| otherwise =
gId f +++
prTList " " [prParenth ("fg" +++ x) | x <- vars]
--type HSkeleton = [(OIdent, [(OIdent, [OIdent])])]
hSkeleton :: PGF -> (String,HSkeleton)
hSkeleton gr =
(showCId (absname gr),
[(showCId c, [(showCId f, map showCId cs) | (f, (cs,_)) <- fs]) |
fs@((_, (_,c)):_) <- fns]
)
where
fns = groupBy valtypg (sortBy valtyps (map jty (Map.assocs (funs (abstract gr)))))
valtyps (_, (_,x)) (_, (_,y)) = compare x y
valtypg (_, (_,x)) (_, (_,y)) = x == y
jty (f,(ty,_,_)) = (f,catSkeleton ty)
updateSkeleton :: OIdent -> HSkeleton -> (OIdent, [OIdent]) -> HSkeleton
updateSkeleton cat skel rule =
case skel of
(cat0,rules):rr | cat0 == cat -> (cat0, rule:rules) : rr
(cat0,rules):rr -> (cat0, rules) : updateSkeleton cat rr rule
isListCat :: (OIdent, [(OIdent, [OIdent])]) -> Bool
isListCat (cat,rules) = "List" `isPrefixOf` cat && length rules == 2
&& ("Base"++c) `elem` fs && ("Cons"++c) `elem` fs
where c = elemCat cat
fs = map fst rules
-- | Gets the element category of a list category.
elemCat :: OIdent -> OIdent
elemCat = drop 4
isBaseFun :: OIdent -> Bool
isBaseFun f = "Base" `isPrefixOf` f
isConsFun :: OIdent -> Bool
isConsFun f = "Cons" `isPrefixOf` f
baseSize :: (OIdent, [(OIdent, [OIdent])]) -> Int
baseSize (_,rules) = length bs
where Just (_,bs) = find (("Base" `isPrefixOf`) . fst) rules