forked from GitHub/gf-core
231 lines
8.6 KiB
Haskell
231 lines
8.6 KiB
Haskell
----------------------------------------------------------------------
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-- |
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-- Module : GFCCtoHaskell
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-- Maintainer : Aarne Ranta
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-- Stability : (stable)
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-- Portability : (portable)
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--
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-- > CVS $Date: 2005/06/17 12:39:07 $
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-- > CVS $Author: bringert $
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-- > CVS $Revision: 1.8 $
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--
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-- to write a GF abstract grammar into a Haskell module with translations from
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-- data objects into GF trees. Example: GSyntax for Agda.
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-- AR 11/11/1999 -- 7/12/2000 -- 18/5/2004
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-----------------------------------------------------------------------------
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module GF.Compile.GFCCtoHaskell (grammar2haskell) where
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import PGF.CId
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import PGF.Data
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import PGF.Macros
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import GF.Data.Operations
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import GF.Infra.Option
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import GF.Text.UTF8
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import Data.List --(isPrefixOf, find, intersperse)
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import qualified Data.Map as Map
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type Prefix = String -> String
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-- | the main function
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grammar2haskell :: Options
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-> String -- ^ Module name.
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-> PGF
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-> String
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grammar2haskell opts name gr = encodeUTF8 $ foldr (++++) [] $
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pragmas ++ haskPreamble name ++ [types, gfinstances gId lexical gr']
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where gr' = hSkeleton gr
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gadt = haskellOption opts HaskellGADT
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lexical cat = haskellOption opts HaskellLexical && isLexicalCat opts cat
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gId | haskellOption opts HaskellNoPrefix = id
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| otherwise = ("G"++)
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pragmas | gadt = ["{-# OPTIONS_GHC -fglasgow-exts #-}"]
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| otherwise = []
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types | gadt = datatypesGADT gId lexical gr'
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| otherwise = datatypes gId lexical gr'
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haskPreamble name =
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[
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"module " ++ name ++ " where",
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"",
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"import PGF",
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"----------------------------------------------------",
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"-- automatic translation from GF to Haskell",
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"----------------------------------------------------",
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"",
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"class Gf a where",
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" gf :: a -> Tree",
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" fg :: Tree -> a",
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"",
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predefInst "GString" "String" "Lit (LStr s)",
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"",
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predefInst "GInt" "Integer" "Lit (LInt s)",
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"",
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predefInst "GFloat" "Double" "Lit (LFlt s)",
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"",
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"----------------------------------------------------",
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"-- below this line machine-generated",
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"----------------------------------------------------",
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""
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]
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predefInst gtyp typ patt =
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"newtype" +++ gtyp +++ "=" +++ gtyp +++ typ +++ " deriving Show" +++++
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"instance Gf" +++ gtyp +++ "where" ++++
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" gf (" ++ gtyp +++ "s) =" +++ patt ++++
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" fg t =" ++++
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" case t of" ++++
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" " +++ patt +++ " ->" +++ gtyp +++ "s" ++++
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" _ -> error (\"no" +++ gtyp +++ "\" ++ show t)"
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type OIdent = String
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type HSkeleton = [(OIdent, [(OIdent, [OIdent])])]
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datatypes :: Prefix -> (OIdent -> Bool) -> (String,HSkeleton) -> String
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datatypes gId lexical = (foldr (+++++) "") . (filter (/="")) . (map (hDatatype gId lexical)) . snd
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gfinstances :: Prefix -> (OIdent -> Bool) -> (String,HSkeleton) -> String
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gfinstances gId lexical (m,g) = (foldr (+++++) "") $ (filter (/="")) $ (map (gfInstance gId lexical m)) g
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hDatatype :: Prefix -> (OIdent -> Bool) -> (OIdent, [(OIdent, [OIdent])]) -> String
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hDatatype _ _ ("Cn",_) = "" ---
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hDatatype _ _ (cat,[]) = ""
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hDatatype gId _ (cat,rules) | isListCat (cat,rules) =
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"newtype" +++ gId cat +++ "=" +++ gId cat +++ "[" ++ gId (elemCat cat) ++ "]"
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+++ "deriving Show"
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hDatatype gId lexical (cat,rules) =
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"data" +++ gId cat +++ "=" ++
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(if length rules == 1 then "" else "\n ") +++
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foldr1 (\x y -> x ++ "\n |" +++ y) constructors ++++
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" deriving Show"
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where
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constructors = [gId f +++ foldr (+++) "" (map (gId) xx) | (f,xx) <- nonLexicalRules (lexical cat) rules]
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++ if lexical cat then [lexicalConstructor cat +++ "String"] else []
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nonLexicalRules :: Bool -> [(OIdent, [OIdent])] -> [(OIdent, [OIdent])]
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nonLexicalRules False rules = rules
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nonLexicalRules True rules = [r | r@(f,t) <- rules, not (null t)]
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lexicalConstructor :: OIdent -> String
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lexicalConstructor cat = "Lex" ++ cat
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-- GADT version of data types
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datatypesGADT :: Prefix -> (OIdent -> Bool) -> (String,HSkeleton) -> String
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datatypesGADT gId lexical (_,skel) =
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unlines (concatMap (hCatTypeGADT gId) skel)
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+++++
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"data Tree :: * -> * where" ++++ unlines (concatMap (map (" "++) . hDatatypeGADT gId lexical) skel)
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hCatTypeGADT :: Prefix -> (OIdent, [(OIdent, [OIdent])]) -> [String]
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hCatTypeGADT gId (cat,rules)
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= ["type"+++gId cat+++"="+++"Tree"+++gId cat++"_",
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"data"+++gId cat++"_"]
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hDatatypeGADT :: Prefix -> (OIdent -> Bool) -> (OIdent, [(OIdent, [OIdent])]) -> [String]
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hDatatypeGADT gId lexical (cat, rules)
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| isListCat (cat,rules) = [gId cat+++"::"+++"["++gId (elemCat cat)++"]" +++ "->" +++ t]
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| otherwise =
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[ gId f +++ "::" +++ concatMap (\a -> gId a +++ "-> ") args ++ t
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| (f,args) <- nonLexicalRules (lexical cat) rules ]
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++ if lexical cat then [lexicalConstructor cat +++ ":: String ->"+++ t] else []
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where t = "Tree" +++ gId cat ++ "_"
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gfInstance :: Prefix -> (OIdent -> Bool) -> String -> (OIdent, [(OIdent, [OIdent])]) -> String
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gfInstance gId lexical m crs = hInstance gId lexical m crs ++++ fInstance gId lexical m crs
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----hInstance m ("Cn",_) = "" --- seems to belong to an old applic. AR 18/5/2004
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hInstance _ _ m (cat,[]) = ""
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hInstance gId lexical m (cat,rules)
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| isListCat (cat,rules) =
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"instance Gf" +++ gId cat +++ "where" ++++
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" gf (" ++ gId cat +++ "[" ++ concat (intersperse "," baseVars) ++ "])"
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+++ "=" +++ mkRHS ("Base"++ec) baseVars ++++
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" gf (" ++ gId cat +++ "(x:xs)) = "
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++ mkRHS ("Cons"++ec) ["x",prParenth (gId cat+++"xs")]
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-- no show for GADTs
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-- ++++ " gf (" ++ gId cat +++ "xs) = error (\"Bad " ++ cat ++ " value: \" ++ show xs)"
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| otherwise =
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"instance Gf" +++ gId cat +++ "where\n" ++
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unlines ([mkInst f xx | (f,xx) <- nonLexicalRules (lexical cat) rules]
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++ if lexical cat then [" gf (" ++ lexicalConstructor cat +++ "x) = Fun (mkCId x) []"] else [])
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where
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ec = elemCat cat
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baseVars = mkVars (baseSize (cat,rules))
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mkInst f xx = let xx' = mkVars (length xx) in " gf " ++
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(if length xx == 0 then gId f else prParenth (gId f +++ foldr1 (+++) xx')) +++
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"=" +++ mkRHS f xx'
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mkVars n = ["x" ++ show i | i <- [1..n]]
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mkRHS f vars = "Fun (mkCId \"" ++ f ++ "\")" +++
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"[" ++ prTList ", " ["gf" +++ x | x <- vars] ++ "]"
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----fInstance m ("Cn",_) = "" ---
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fInstance _ _ m (cat,[]) = ""
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fInstance gId lexical m (cat,rules) =
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" fg t =" ++++
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" case t of" ++++
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unlines [mkInst f xx | (f,xx) <- nonLexicalRules (lexical cat) rules] ++++
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(if lexical cat then " Fun i [] -> " ++ lexicalConstructor cat +++ "(prCId i)" else "") ++++
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" _ -> error (\"no" +++ cat ++ " \" ++ show t)"
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where
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mkInst f xx =
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" Fun i " ++
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"[" ++ prTList "," xx' ++ "]" +++
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"| i == mkCId \"" ++ f ++ "\" ->" +++ mkRHS f xx'
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where xx' = ["x" ++ show i | (_,i) <- zip xx [1..]]
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mkRHS f vars
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| isListCat (cat,rules) =
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if "Base" `isPrefixOf` f then
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gId cat +++ "[" ++ prTList ", " [ "fg" +++ x | x <- vars ] ++ "]"
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else
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let (i,t) = (init vars,last vars)
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in "let" +++ gId cat +++ "xs = fg " ++ t +++ "in" +++
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gId cat +++ prParenth (prTList ":" (["fg"+++v | v <- i] ++ ["xs"]))
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| otherwise =
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gId f +++
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prTList " " [prParenth ("fg" +++ x) | x <- vars]
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--type HSkeleton = [(OIdent, [(OIdent, [OIdent])])]
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hSkeleton :: PGF -> (String,HSkeleton)
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hSkeleton gr =
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(prCId (absname gr),
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[(prCId c, [(prCId f, map prCId cs) | (f, (cs,_)) <- fs]) |
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fs@((_, (_,c)):_) <- fns]
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)
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where
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fns = groupBy valtypg (sortBy valtyps (map jty (Map.assocs (funs (abstract gr)))))
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valtyps (_, (_,x)) (_, (_,y)) = compare x y
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valtypg (_, (_,x)) (_, (_,y)) = x == y
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jty (f,(ty,_,_)) = (f,catSkeleton ty)
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updateSkeleton :: OIdent -> HSkeleton -> (OIdent, [OIdent]) -> HSkeleton
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updateSkeleton cat skel rule =
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case skel of
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(cat0,rules):rr | cat0 == cat -> (cat0, rule:rules) : rr
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(cat0,rules):rr -> (cat0, rules) : updateSkeleton cat rr rule
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isListCat :: (OIdent, [(OIdent, [OIdent])]) -> Bool
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isListCat (cat,rules) = "List" `isPrefixOf` cat && length rules == 2
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&& ("Base"++c) `elem` fs && ("Cons"++c) `elem` fs
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where c = elemCat cat
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fs = map fst rules
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-- | Gets the element category of a list category.
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elemCat :: OIdent -> OIdent
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elemCat = drop 4
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isBaseFun :: OIdent -> Bool
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isBaseFun f = "Base" `isPrefixOf` f
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isConsFun :: OIdent -> Bool
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isConsFun f = "Cons" `isPrefixOf` f
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baseSize :: (OIdent, [(OIdent, [OIdent])]) -> Int
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baseSize (_,rules) = length bs
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where Just (_,bs) = find (("Base" `isPrefixOf`) . fst) rules
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