Files
gf-core/src-3.0/GF/API/GrammarToTransfer.hs

95 lines
3.2 KiB
Haskell

----------------------------------------------------------------------
-- |
-- Module : GrammarToTransfer
-- Maintainer : Björn Bringert
-- Stability : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/06/17 12:39:07 $
-- > CVS $Author: bringert $
-- > CVS $Revision: 1.8 $
--
-- Creates a data type definition in the transfer language
-- for an abstract module.
-----------------------------------------------------------------------------
module GF.API.GrammarToTransfer (grammar2transfer) where
import qualified GF.Canon.GFC as GFC
import qualified GF.Grammar.Abstract as A
import GF.Grammar.Macros
import GF.Infra.Modules
import GF.Data.Operations
import Transfer.Syntax.Abs as S
import Transfer.Syntax.Print
-- | the main function
grammar2transfer :: GFC.CanonGrammar -> String
grammar2transfer gr = printTree $ S.Module imports decls
where
cat = S.Ident "Cat" -- FIXME
tree = S.Ident "Tree" -- FIXME
defs = concat [tree2list (jments m) | im@(_,ModMod m) <- modules gr, isModAbs m]
-- get category name and context
cats = [(cat, c) | (cat,GFC.AbsCat c _) <- defs]
-- get function name and type
funs = [(fun, typ) | (fun,GFC.AbsFun typ _) <- defs]
name = ifNull "UnknownModule" (symid . last) [n | (n,ModMod m) <- modules gr, isModAbs m]
imports = [Import (S.Ident "prelude")]
decls = [cats2cat cat tree cats, funs2tree cat tree funs] ++ instances tree
-- | Create a declaration of the type of categories given a list
-- of category names and their contexts.
cats2cat :: S.Ident -- ^ the name of the Cat type
-> S.Ident -- ^ the name of the Tree type
-> [(A.Ident,A.Context)] -> Decl
cats2cat cat tree = S.DataDecl cat S.EType . map (uncurry catCons)
where
catCons i c = S.ConsDecl (id2id i) (catConsType c)
catConsType = foldr pi (S.EVar cat)
pi (i,x) t = mkPi (id2pv i) (addTree tree $ term2exp x) t
funs2tree :: S.Ident -- ^ the name of the Cat type
-> S.Ident -- ^ the name of the Tree type
-> [(A.Ident,A.Type)] -> Decl
funs2tree cat tree =
S.DataDecl tree (S.EPiNoVar (S.EVar cat) S.EType) . map (uncurry funCons)
where
funCons i t = S.ConsDecl (id2id i) (addTree tree $ term2exp t)
term2exp :: A.Term -> S.Exp
term2exp t = case t of
A.Vr i -> S.EVar (id2id i)
A.App t1 t2 -> S.EApp (term2exp t1) (term2exp t2)
A.Abs i t1 -> S.EAbs (id2pv i) (term2exp t1)
A.Prod i t1 t2 -> mkPi (id2pv i) (term2exp t1) (term2exp t2)
A.Q m i -> S.EVar (id2id i)
_ -> error $ "term2exp: can't handle " ++ show t
mkPi :: S.VarOrWild -> S.Exp -> S.Exp -> S.Exp
mkPi VWild t e = S.EPiNoVar t e
mkPi v t e = S.EPi v t e
id2id :: A.Ident -> S.Ident
id2id = S.Ident . symid
id2pv :: A.Ident -> S.VarOrWild
id2pv i = case symid i of
"h_" -> S.VWild -- FIXME: hacky?
x -> S.VVar (S.Ident x)
-- FIXME: I think this is not general enoguh.
addTree :: S.Ident -> S.Exp -> S.Exp
addTree tree x = case x of
S.EPi i t e -> S.EPi i (addTree tree t) (addTree tree e)
S.EPiNoVar t e -> S.EPiNoVar (addTree tree t) (addTree tree e)
e -> S.EApp (S.EVar tree) e
instances :: S.Ident -> [S.Decl]
instances tree = [DeriveDecl (S.Ident "Eq") tree,
DeriveDecl (S.Ident "Compos") tree]