forked from GitHub/gf-core
191 lines
6.7 KiB
Haskell
191 lines
6.7 KiB
Haskell
----------------------------------------------------------------------
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-- |
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-- Module : GrammarToHaskell
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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.API.GrammarToHaskell (grammar2haskell) where
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import qualified GF.Canon.GFC as GFC
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import GF.Grammar.Macros
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import GF.Infra.Modules
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import GF.Data.Operations
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import Data.List (isPrefixOf, find, intersperse)
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-- | the main function
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grammar2haskell :: GFC.CanonGrammar -> String
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grammar2haskell gr = foldr (++++) [] $
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haskPreamble ++ [datatypes gr', gfinstances gr', fginstances gr']
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where gr' = hSkeleton gr
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-- | by this you can prefix all identifiers with stg; the default is 'G'
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gId :: OIdent -> OIdent
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gId i = 'G':i
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haskPreamble =
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[
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"module GSyntax where",
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"",
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"import GF.Infra.Ident",
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"import GF.Grammar.Grammar",
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"import GF.Grammar.PrGrammar",
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"import GF.Grammar.Macros",
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"import GF.Data.Operations",
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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 gf :: a -> Trm",
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"class Fg a where fg :: Trm -> a",
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"",
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predefInst "GString" "String" "K s",
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"",
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predefInst "GInt" "Integer" "EInt s",
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"",
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predefInst "GFloat" "Double" "EFloat 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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"instance Fg" +++ gtyp +++ "where" ++++
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" fg t =" ++++
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" case termForm t of" ++++
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" Ok ([]," +++ patt +++ ",[]) ->" +++ gtyp +++ "s" ++++
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" _ -> error (\"no" +++ gtyp +++ "\" ++ prt t)"
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type OIdent = String
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type HSkeleton = [(OIdent, [(OIdent, [OIdent])])]
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datatypes, gfinstances, fginstances :: (String,HSkeleton) -> String
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datatypes = (foldr (+++++) "") . (filter (/="")) . (map hDatatype) . snd
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gfinstances (m,g) = (foldr (+++++) "") $ (filter (/="")) $ (map (hInstance m)) g
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fginstances (m,g) = (foldr (+++++) "") $ (filter (/="")) $ (map (fInstance m)) g
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hDatatype :: (OIdent, [(OIdent, [OIdent])]) -> String
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hInstance, fInstance :: String -> (OIdent, [(OIdent, [OIdent])]) -> String
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hDatatype ("Cn",_) = "" ---
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hDatatype (cat,[]) = ""
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hDatatype (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 (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)
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[gId f +++ foldr (+++) "" (map gId xx) | (f,xx) <- rules] ++++
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" deriving Show"
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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 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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" gf (" ++ gId cat +++ "xs) = error (\"Bad " ++ cat ++ " value: \" ++ show xs)"
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| otherwise =
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"instance Gf" +++ gId cat +++ "where" ++
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(if length rules == 1 then "" else "\n") +++
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foldr1 (\x y -> x ++ "\n" +++ y) [mkInst f xx | (f,xx) <- rules]
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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 = "appqc \"" ++ m ++ "\" \"" ++ 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 m (cat,rules) =
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"instance Fg" +++ gId cat +++ "where" ++++
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" fg t =" ++++
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" case termForm t of" ++++
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foldr1 (\x y -> x ++ "\n" ++ y) [mkInst f xx | (f,xx) <- rules] ++++
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" _ -> error (\"no" +++ cat ++ " \" ++ prt t)"
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where
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mkInst f xx =
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" Ok ([], Q (IC \"" ++ m ++ "\") (IC \"" ++ f ++ "\")," ++
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"[" ++ prTList "," xx' ++ "])" +++
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"->" +++ 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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hSkeleton :: GFC.CanonGrammar -> (String,HSkeleton)
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hSkeleton gr = (name,collectR rules [(c,[]) | c <- cats]) where
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collectR rr hh =
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case rr of
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(fun,typ):rs -> case catSkeleton typ of
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Ok (cats,cat) ->
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collectR rs (updateSkeleton (symid (snd cat)) hh (fun,
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map (symid . snd) cats))
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_ -> collectR rs hh
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_ -> hh
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cats = [symid cat | (cat,GFC.AbsCat _ _) <- defs]
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rules = [(symid fun, typ) | (fun,GFC.AbsFun typ _) <- defs]
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defs = concat [tree2list (jments m) | im@(_,ModMod m) <- modules gr, isModAbs m]
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name = ifNull "UnknownModule" (symid . last) [n | (n,ModMod m) <- modules gr, isModAbs m]
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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 |