mirror of
https://github.com/GrammaticalFramework/gf-core.git
synced 2026-04-27 13:32:51 -06:00
422 lines
18 KiB
Haskell
422 lines
18 KiB
Haskell
{-# LANGUAGE RankNTypes, CPP #-}
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-- | Functions for computing the values of terms in the concrete syntax, in
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-- | preparation for PMCFG generation.
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module GF.Compile.Compute.Concrete
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(normalForm,
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Value(..), Env, value2term, eval
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) where
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import Prelude hiding ((<>)) -- GHC 8.4.1 clash with Text.PrettyPrint
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import GF.Grammar hiding (Env, VGen, VApp, VRecType)
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import GF.Grammar.Lookup(lookupResDef,allParamValues)
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import GF.Grammar.Predef
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import GF.Grammar.Lockfield(isLockLabel,lockRecType) --unlockRecord,lockLabel
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import GF.Grammar.Printer
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import GF.Data.Str(Str,glueStr,str2strings,str,sstr,plusStr,strTok)
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import GF.Data.Operations(Err(..),err,errIn,maybeErr,mapPairsM)
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import GF.Data.Utilities(mapFst,mapSnd)
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import GF.Infra.Option
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import Data.STRef
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import Data.Maybe(fromMaybe)
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import Data.List
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import Data.Char
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import Control.Monad
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import Control.Monad.ST
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import Control.Applicative
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import qualified Control.Monad.Fail as Fail
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import qualified Data.Map as Map
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import GF.Text.Pretty
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-- * Main entry points
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normalForm :: Grammar -> L Ident -> Term -> Term
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normalForm gr loc t =
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case runEvalM gr (eval [] t [] >>= value2term 0) of
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Left msg -> error (render (ppL loc msg))
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Right [t] -> t
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Right ts -> FV ts
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data ThunkState s
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= Unevaluated (Env s) Term
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| Evaluated (Value s)
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| Unbound {-# UNPACK #-} !MetaId
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type Thunk s = STRef s (ThunkState s)
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type Env s = [(Ident,Thunk s)]
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data Value s
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= VApp QIdent [Thunk s]
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| VMeta (Thunk s) (Env s) [Thunk s]
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| VSusp (Thunk s) (Env s) [Thunk s] (Thunk s -> EvalM s (Value s))
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| VGen {-# UNPACK #-} !Int [Thunk s]
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| VClosure (Env s) Term
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| VProd BindType Ident (Value s) (Value s)
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| VRecType [(Label, Value s)]
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| VR [(Label, Thunk s)]
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| VP (Value s) Label [Thunk s]
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| VTable (Value s) (Value s)
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| VT TInfo [Case]
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| VV Type [Thunk s]
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| VS (Value s) (Thunk s) [Thunk s]
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| VSort Ident
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| VInt Integer
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| VFlt Double
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| VStr String
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| VC [Value s]
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eval env (Vr x) vs = case lookup x env of
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Just tnk -> force tnk vs
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Nothing -> evalError ("Variable" <+> pp x <+> "is not in scope")
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eval env (Sort s) [] = return (VSort s)
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eval env (EInt n) [] = return (VInt n)
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eval env (EFloat d) [] = return (VFlt d)
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eval env (K t) [] = return (VStr t)
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eval env Empty [] = return (VC [])
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eval env (App t1 t2) vs = do tnk <- newThunk env t2
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eval env t1 (tnk : vs)
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eval env (Abs b x t) [] = return (VClosure env (Abs b x t))
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eval env (Abs b x t) (v:vs) = eval ((x,v):env) t vs
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eval env (Meta i) vs = do tnk <- newMeta i
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return (VMeta tnk env vs)
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eval env (ImplArg t) [] = eval env t []
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eval env (Prod b x t1 t2)[] = do v1 <- eval env t1 []
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return (VProd b x v1 (VClosure env (Abs b x t2)))
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eval env (Typed t ty) vs = eval env t vs
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eval env (RecType lbls) [] = do lbls <- mapM (\(lbl,ty) -> fmap ((,) lbl) (eval env ty [])) lbls
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return (VRecType lbls)
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eval env (R as) [] = do as <- mapM (\(lbl,(_,t)) -> fmap ((,) lbl) (newThunk env t)) as
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return (VR as)
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eval env (P t lbl) vs = do v <- eval env t []
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case v of
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VR as -> case lookup lbl as of
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Nothing -> evalError ("Missing value for label" <+> pp lbl $$
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"in record" <+> pp t)
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Just tnk -> force tnk vs
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v -> return (VP v lbl vs)
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eval env (Table t1 t2) [] = do v1 <- eval env t1 []
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v2 <- eval env t2 []
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return (VTable v1 v2)
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eval env (T i cs) [] = return (VT i cs)
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eval env (V ty ts) [] = do tnks <- mapM (newThunk env) ts
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return (VV ty tnks)
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eval env t@(S t1 t2) vs = do v1 <- eval env t1 []
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tnk2 <- newThunk env t2
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let v0 = VS v1 tnk2 vs
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case v1 of
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VT _ cs -> patternMatch v0 (map (\(p,t) -> (env,[p],tnk2:vs,t)) cs)
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v1 -> return v0
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eval env (Let (x,(_,t1)) t2) vs = do tnk <- newThunk env t1
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eval ((x,tnk):env) t2 vs
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eval env (Q q@(m,id)) vs
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| m == cPredef = do vs' <- mapM (flip force []) vs
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mb_res <- evalPredef id vs'
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case mb_res of
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Just res -> return res
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Nothing -> return (VApp q vs)
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| otherwise = do t <- lookupGlobal q
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eval env t vs
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eval env (QC q) vs = return (VApp q vs)
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eval env (C t1 t2) [] = do v1 <- eval env t1 []
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v2 <- eval env t2 []
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case (v1,v2) of
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(VC vs1,VC vs2) -> return (VC (vs1++vs2))
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(VC vs1,v2 ) -> return (VC (vs1++[v2]))
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(v1, VC vs2) -> return (VC ([v1]++vs2))
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(v1, v2 ) -> return (VC [v1,v2])
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eval env t@(Glue t1 t2) [] = do v1 <- eval env t1 []
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v2 <- eval env t2 []
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case liftM2 (++) (value2string v1) (value2string v2) of
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Just s -> return (string2value s)
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Nothing -> evalError ("Cannot reduce term" <+> pp t)
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eval env (FV ts) vs = msum [eval env t vs | t <- ts]
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eval env (Error msg) vs = fail msg
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eval env t vs = evalError ("Cannot reduce term" <+> pp t)
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apply v [] = return v
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apply (VApp f vs0) vs = return (VApp f (vs0++vs))
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apply (VMeta m env vs0) vs = return (VMeta m env (vs0++vs))
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apply (VGen i vs0) vs = return (VGen i (vs0++vs))
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apply (VClosure env (Abs b x t)) (v:vs) = eval ((x,v):env) t vs
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evalPredef id [v]
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| id == cLength = return (fmap VInt (liftM genericLength (value2string v)))
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evalPredef id [v1,v2]
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| id == cTake = return (fmap string2value (liftM2 genericTake (value2int v1) (value2string v2)))
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evalPredef id [v1,v2]
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| id == cDrop = return (fmap string2value (liftM2 genericDrop (value2int v1) (value2string v2)))
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evalPredef id [v1,v2]
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| id == cTk = return (fmap string2value (liftM2 genericTk (value2int v1) (value2string v2)))
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where
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genericTk n = reverse . genericTake n . reverse
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evalPredef id [v1,v2]
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| id == cDp = return (fmap string2value (liftM2 genericDp (value2int v1) (value2string v2)))
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where
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genericDp n = reverse . genericDrop n . reverse
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evalPredef id [v]
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| id == cIsUpper= return (fmap toPBool (liftM (all isUpper) (value2string v)))
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evalPredef id [v]
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| id == cToUpper= return (fmap string2value (liftM (map toUpper) (value2string v)))
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evalPredef id [v]
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| id == cToLower= return (fmap string2value (liftM (map toLower) (value2string v)))
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evalPredef id [v1,v2]
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| id == cEqStr = return (fmap toPBool (liftM2 (==) (value2string v1) (value2string v2)))
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evalPredef id [v1,v2]
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| id == cOccur = return (fmap toPBool (liftM2 occur (value2string v1) (value2string v2)))
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evalPredef id [v1,v2]
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| id == cOccurs = return (fmap toPBool (liftM2 occurs (value2string v1) (value2string v2)))
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evalPredef id [v1,v2]
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| id == cEqInt = return (fmap toPBool (liftM2 (==) (value2int v1) (value2int v2)))
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evalPredef id [v1,v2]
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| id == cLessInt= return (fmap toPBool (liftM2 (<) (value2int v1) (value2int v2)))
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evalPredef id [v1,v2]
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| id == cPlus = return (fmap VInt (liftM2 (+) (value2int v1) (value2int v2)))
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evalPredef id [v]
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| id == cError = case value2string v of
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Just msg -> fail msg
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Nothing -> return Nothing
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evalPredef id vs = return Nothing
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toPBool True = VApp (cPredef,cPTrue) []
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toPBool False = VApp (cPredef,cPFalse) []
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occur s1 [] = False
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occur s1 s2@(_:tail) = check s1 s2
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where
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check xs [] = False
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check [] ys = True
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check (x:xs) (y:ys)
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| x == y = check xs ys
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check _ _ = occur s1 tail
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occurs cs s2 = any (\c -> elem c s2) cs
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patternMatch v0 [] = fail "No matching pattern found"
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patternMatch v0 ((env0,ps,args0,t):eqs) = match env0 ps eqs args0
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where
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match env [] eqs args = eval env t args
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match env (PT ty p :ps) eqs args = match env (p:ps) eqs args
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match env (PAlt p1 p2:ps) eqs args = match env (p1:ps) ((env,p2:ps,args,t):eqs) args
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match env (PM q :ps) eqs args = do t <- lookupGlobal q
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case t of
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EPatt _ _ p -> match env (p:ps) eqs args
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_ -> evalError $ hang "Expected pattern macro:" 4
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(pp t)
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match env (PV v :ps) eqs (arg:args) = match ((v,arg):env) ps eqs args
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match env (PAs v p :ps) eqs (arg:args) = match ((v,arg):env) (p:ps) eqs (arg:args)
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match env (PW :ps) eqs (arg:args) = match env ps eqs args
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match env (PTilde _ :ps) eqs (arg:args) = match env ps eqs args
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match env (p :ps) eqs (arg:args) = do
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v <- force arg []
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case (p,v) of
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(p, VMeta i envi vs ) -> return (VSusp i envi vs (\tnk -> match env (p:ps) eqs (tnk:args)))
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(p, VGen i vs ) -> return v0
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(p, VSusp i envi vs k) -> return (VSusp i envi vs (\tnk -> match env (p:ps) eqs (tnk:args)))
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(PP q qs, VApp r tnks)
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| q == r -> match env (qs++ps) eqs (tnks++args)
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(PR pas, VR as) -> matchRec env pas as ps eqs args
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(PString s1, VStr s2)
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| s1 == s2 -> match env ps eqs args
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(PString s1, VC [])
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| null s1 -> match env ps eqs args
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(PSeq min1 max1 p1 min2 max2 p2,v)
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-> case value2string v of
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Just s -> do let n = length s
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lo = min1 `max` (n-fromMaybe n max2)
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hi = (n-min2) `min` fromMaybe n max1
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(ds,cs) = splitAt lo s
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eqs <- matchStr env (p1:p2:ps) eqs (hi-lo) (reverse ds) cs args
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patternMatch v0 eqs
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Nothing -> return v0
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(PRep minp maxp p, v)
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-> case value2string v of
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Just s -> do let n = length s `div` (max minp 1)
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eqs <- matchRep env n minp maxp p minp maxp p ps ((env,PString []:ps,(arg:args),t) : eqs) (arg:args)
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patternMatch v0 eqs
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Nothing -> return v0
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(PChar, VStr [_]) -> match env ps eqs args
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(PChars cs, VStr [c])
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| elem c cs -> match env ps eqs args
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(PInt n, VInt m)
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| n == m -> match env ps eqs args
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(PFloat n, VFlt m)
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| n == m -> match env ps eqs args
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_ -> patternMatch v0 eqs
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matchRec env [] as ps eqs args = match env ps eqs args
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matchRec env ((lbl,p):pas) as ps eqs args =
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case lookup lbl as of
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Just tnk -> matchRec env pas as (p:ps) eqs (tnk:args)
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Nothing -> evalError ("Missing value for label" <+> pp lbl)
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matchStr env ps eqs i ds [] args = do
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arg1 <- newEvaluatedThunk (string2value (reverse ds))
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arg2 <- newEvaluatedThunk (string2value [])
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return ((env,ps,arg1:arg2:args,t) : eqs)
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matchStr env ps eqs 0 ds cs args = do
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arg1 <- newEvaluatedThunk (string2value (reverse ds))
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arg2 <- newEvaluatedThunk (string2value cs)
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return ((env,ps,arg1:arg2:args,t) : eqs)
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matchStr env ps eqs i ds (c:cs) args = do
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arg1 <- newEvaluatedThunk (string2value (reverse ds))
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arg2 <- newEvaluatedThunk (string2value (c:cs))
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eqs <- matchStr env ps eqs (i-1 :: Int) (c:ds) cs args
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return ((env,ps,arg1:arg2:args,t) : eqs)
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matchRep env 0 minp maxp p minq maxq q ps eqs args = do
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return eqs
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matchRep env n minp maxp p minq maxq q ps eqs args = do
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matchRep env (n-1) minp maxp p (minp+minq) (liftM2 (+) maxp maxq) (PSeq minp maxp p minq maxq q) ps ((env,q:ps,args,t) : eqs) args
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value2term i (VApp q tnks) =
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foldM (\e1 tnk -> fmap (App e1) (force tnk [] >>= value2term i)) (QC q) tnks
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value2term i (VMeta m env tnks) = do
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res <- zonk m tnks
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case res of
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Right i -> foldM (\e1 tnk -> fmap (App e1) (force tnk [] >>= value2term i)) (Meta i) tnks
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Left v -> value2term i v
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value2term i (VGen j tnks) =
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foldM (\e1 tnk -> fmap (App e1) (force tnk [] >>= value2term i)) (Vr (identS ('v':show j))) tnks
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value2term i (VClosure env (Abs b x t)) = do
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tnk <- newGen i
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v <- eval ((x,tnk):env) t []
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t <- value2term (i+1) v
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return (Abs b (identS ('v':show i)) t)
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value2term i (VProd b x v1 v2) = do
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t1 <- value2term i v1
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t2 <- value2term i v2
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return (Prod b x t1 t2)
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value2term i (VRecType lbls) = do
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lbls <- mapM (\(lbl,v) -> fmap ((,) lbl) (value2term i v)) lbls
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return (RecType lbls)
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value2term i (VR as) = do
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as <- mapM (\(lbl,tnk) -> fmap (\t -> (lbl,(Nothing,t))) (force tnk [] >>= value2term i)) as
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return (R as)
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value2term i (VP v lbl tnks) = do
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t <- value2term i v
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foldM (\e1 tnk -> fmap (App e1) (force tnk [] >>= value2term i)) (P t lbl) tnks
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value2term i (VTable v1 v2) = do
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t1 <- value2term i v1
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t2 <- value2term i v2
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return (Table t1 t2)
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value2term i (VT ti cs) = return (T ti cs)
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value2term i (VV ty tnks) = do ts <- mapM (\tnk -> force tnk [] >>= value2term i) tnks
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return (V ty ts)
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value2term i (VS v1 tnk2 tnks) = do t1 <- value2term i v1
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t2 <- force tnk2 [] >>= value2term i
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foldM (\e1 tnk -> fmap (App e1) (force tnk [] >>= value2term i)) (S t1 t2) tnks
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value2term i (VSort s) = return (Sort s)
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value2term i (VStr tok) = return (K tok)
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value2term i (VInt n) = return (EInt n)
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value2term i (VFlt n) = return (EFloat n)
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value2term i (VC vs) = do
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ts <- mapM (value2term i) vs
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case ts of
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[] -> return Empty
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(t:ts) -> return (foldl C t ts)
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value2string (VStr s) = Just s
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value2string (VC vs) = fmap unwords (mapM value2string vs)
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value2string _ = Nothing
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string2value s =
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case words s of
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[] -> VC []
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[w] -> VStr w
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ws -> VC (map VStr ws)
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value2int (VInt n) = Just n
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value2int _ = Nothing
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-----------------------------------------------------------------------
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-- * Evaluation monad
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type MetaThunks s = Map.Map MetaId (Thunk s)
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type Cont s r = MetaThunks s -> r -> ST s (Either Doc r)
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newtype EvalM s a = EvalM (forall r . Grammar -> (a -> Cont s r) -> Cont s r)
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instance Functor (EvalM s) where
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fmap f (EvalM g) = EvalM (\gr k -> g gr (k . f))
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instance Applicative (EvalM s) where
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pure x = EvalM (\gr k -> k x)
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(EvalM f) <*> (EvalM x) = EvalM (\gr k -> f gr (\f -> x gr (\x -> k (f x))))
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instance Monad (EvalM s) where
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(EvalM f) >>= g = EvalM (\gr k -> f gr (\x -> case g x of
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EvalM g -> g gr k))
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#if !(MIN_VERSION_base(4,13,0))
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-- Monad(fail) will be removed in GHC 8.8+
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fail = Fail.fail
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#endif
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instance Fail.MonadFail (EvalM s) where
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fail msg = EvalM (\gr k _ r -> return (Left (pp msg)))
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instance Alternative (EvalM s) where
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empty = EvalM (\gr k _ r -> return (Right r))
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(EvalM f) <|> (EvalM g) = EvalM $ \gr k mt r -> do
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res <- f gr k mt r
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case res of
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Left msg -> return (Left msg)
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Right r -> g gr k mt r
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instance MonadPlus (EvalM s) where
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runEvalM :: Grammar -> (forall s . EvalM s a) -> Either Doc [a]
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runEvalM gr f =
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case runST (case f of
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EvalM f -> f gr (\x mt xs -> return (Right (x:xs))) Map.empty []) of
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Left msg -> Left msg
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Right xs -> Right (reverse xs)
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evalError :: Doc -> EvalM s a
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evalError msg = EvalM (\gr k _ r -> return (Left msg))
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lookupGlobal :: QIdent -> EvalM s Term
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lookupGlobal q = EvalM $ \gr k mt r -> do
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case lookupResDef gr q of
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Ok t -> k t mt r
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Bad msg -> return (Left (pp msg))
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newThunk env t = EvalM $ \gr k mt r -> do
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tnk <- newSTRef (Unevaluated env t)
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k tnk mt r
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newEvaluatedThunk v = EvalM $ \gr k mt r -> do
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tnk <- newSTRef (Evaluated v)
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k tnk mt r
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newMeta i = EvalM $ \gr k mt r ->
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if i == 0
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then do tnk <- newSTRef (Unbound i)
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|
k tnk mt r
|
|
else case Map.lookup i mt of
|
|
Just tnk -> k tnk mt r
|
|
Nothing -> do tnk <- newSTRef (Unbound i)
|
|
k tnk (Map.insert i tnk mt) r
|
|
|
|
newGen i = EvalM $ \gr k mt r -> do
|
|
tnk <- newSTRef (Evaluated (VGen i []))
|
|
k tnk mt r
|
|
|
|
force tnk vs = EvalM $ \gr k mt r -> do
|
|
s <- readSTRef tnk
|
|
case s of
|
|
Unevaluated env t -> case eval env t vs of
|
|
EvalM f -> f gr (\v mt r -> do writeSTRef tnk (Evaluated v)
|
|
r <- k v mt r
|
|
writeSTRef tnk s
|
|
return r) mt r
|
|
Evaluated v -> case apply v vs of
|
|
EvalM f -> f gr k mt r
|
|
|
|
zonk tnk vs = EvalM $ \gr k mt r -> do
|
|
s <- readSTRef tnk
|
|
case s of
|
|
Evaluated v -> case apply v vs of
|
|
EvalM f -> f gr (k . Left) mt r
|
|
Unbound i -> k (Right i) mt r
|