module PGF.Generate
( generateAll, generateAllDepth
, generateFrom, generateFromDepth
, generateRandom, generateRandomDepth
, generateRandomFrom, generateRandomFromDepth
, prove
) where
import PGF.CId
import PGF.Data
import PGF.Expr
import PGF.Macros
import PGF.TypeCheck
import PGF.Probabilistic
import Data.Maybe (fromMaybe)
import qualified Data.Map as Map
import qualified Data.IntMap as IntMap
import Control.Monad
import Control.Monad.Identity
import System.Random
generateAll :: PGF -> Type -> [Expr]
generateAll pgf ty = generateAllDepth pgf ty Nothing
generateAllDepth :: PGF -> Type -> Maybe Int -> [Expr]
generateAllDepth pgf ty dp = generate () pgf ty dp
generateFrom :: PGF -> Expr -> [Expr]
generateFrom pgf ex = generateFromDepth pgf ex Nothing
generateFromDepth :: PGF -> Expr -> Maybe Int -> [Expr]
generateFromDepth pgf e dp =
[e | (_,_,e) <- snd $ runTcM (abstract pgf)
(generateForMetas (prove dp) e)
emptyMetaStore ()]
generateRandom :: RandomGen g => g -> PGF -> Type -> [Expr]
generateRandom g pgf ty = generateRandomDepth g pgf ty Nothing
generateRandomDepth :: RandomGen g => g -> PGF -> Type -> Maybe Int -> [Expr]
generateRandomDepth g pgf ty dp = restart g (\g -> generate (Identity g) pgf ty dp)
generateRandomFrom :: RandomGen g => g -> PGF -> Expr -> [Expr]
generateRandomFrom g pgf e = generateRandomFromDepth g pgf e Nothing
generateRandomFromDepth :: RandomGen g => g -> PGF -> Expr -> Maybe Int -> [Expr]
generateRandomFromDepth g pgf e dp =
restart g (\g -> [e | (_,ms,e) <- snd $ runTcM (abstract pgf)
(generateForMetas (prove dp) e)
emptyMetaStore (Identity g)])
generate :: Selector sel => sel -> PGF -> Type -> Maybe Int -> [Expr]
generate sel pgf ty dp =
[e | (_,ms,e) <- snd $ runTcM (abstract pgf)
(prove dp emptyScope (TTyp [] ty) >>= checkResolvedMetaStore emptyScope)
emptyMetaStore sel]
prove :: Selector sel => Maybe Int -> Scope -> TType -> TcM sel Expr
prove dp scope (TTyp env1 (DTyp hypos1 cat es1)) = do
vs1 <- mapM (PGF.TypeCheck.eval env1) es1
let scope' = exScope scope env1 hypos1
(fe,TTyp env2 (DTyp hypos2 _ es2)) <- select cat scope' dp
case dp of
Just 0 | not (null hypos2) -> mzero
_ -> return ()
(env2,args) <- mkEnv scope' env2 hypos2
vs2 <- mapM (PGF.TypeCheck.eval env2) es2
sequence_ [eqValue mzero suspend (scopeSize scope') v1 v2 | (v1,v2) <- zip vs1 vs2]
es <- mapM (descend scope') args
return (abs hypos1 (foldl EApp fe es))
where
suspend i c = do
mv <- getMeta i
case mv of
MBound e -> c e
MUnbound x scope tty cs -> setMeta i (MUnbound x scope tty (c:cs))
abs [] e = e
abs ((bt,x,ty):hypos) e = EAbs bt x (abs hypos e)
exScope scope env [] = scope
exScope scope env ((bt,x,ty):hypos) =
let env' | x /= wildCId = VGen (scopeSize scope) [] : env
| otherwise = env
in exScope (addScopedVar x (TTyp env ty) scope) env' hypos
mkEnv scope env [] = return (env,[])
mkEnv scope env ((bt,x,ty):hypos) = do
(env,arg) <- if x /= wildCId
then do i <- newMeta scope (TTyp env ty)
return (VMeta i (scopeEnv scope) [] : env,Right (EMeta i))
else return (env,Left (TTyp env ty))
(env,args) <- mkEnv scope env hypos
return (env,(bt,arg):args)
descend scope (bt,arg) = do
let dp' = fmap (flip () 1) dp
e <- case arg of
Right e -> return e
Left tty -> prove dp' scope tty
e <- case bt of
Implicit -> return (EImplArg e)
Explicit -> return e
return e
restart :: RandomGen g => g -> (g -> [a]) -> [a]
restart g f =
let (g1,g2) = split g
in case f g1 of
[] -> []
(x:xs) -> x : restart g2 f
instance Selector () where
splitSelector s = (s,s)
select cat scope dp = do
gens <- typeGenerators scope cat
TcM (\abstr k h -> iter k gens)
where
iter k [] ms s = id
iter k ((_,e,tty):fns) ms s = k (e,tty) ms s . iter k fns ms s
instance RandomGen g => Selector (Identity g) where
splitSelector (Identity g) = let (g1,g2) = split g
in (Identity g1, Identity g2)
select cat scope dp = do
gens <- typeGenerators scope cat
TcM (\abstr k h -> iter k 1.0 gens)
where
iter k p [] ms (Identity g) = id
iter k p gens ms (Identity g) = let (d,g') = randomR (0.0,p) g
(g1,g2) = split g'
(p',e_ty,gens') = hit d gens
in k e_ty ms (Identity g1) . iter k (pp') gens' ms (Identity g2)
hit :: Double -> [(Double,Expr,TType)] -> (Double,(Expr,TType),[(Double,Expr,TType)])
hit d (gen@(p,e,ty):gens)
| d < p || null gens = (p,(e,ty),gens)
| otherwise = let (p',e_ty',gens') = hit (dp) gens
in (p',e_ty',gen:gens')