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module PGF.Generate where
import PGF.CId
import PGF.Data
import PGF.Macros
import qualified Data.Map as M
import System.Random
-- generate an infinite list of trees exhaustively
generate :: PGF -> CId -> Maybe Int -> [Tree]
generate pgf cat dp = concatMap (\i -> gener i cat) depths
where
gener 0 c = [Fun f [] | (f, ([],_)) <- fns c]
gener i c = [
tr |
(f, (cs,_)) <- fns c,
let alts = map (gener (i-1)) cs,
ts <- combinations alts,
let tr = Fun f ts,
depth tr >= i
]
fns c = [(f,catSkeleton ty) | (f,ty) <- functionsToCat pgf c]
depths = maybe [0 ..] (\d -> [0..d]) dp
-- generate an infinite list of trees randomly
genRandom :: StdGen -> PGF -> CId -> [Tree]
genRandom gen pgf cat = genTrees (randomRs (0.0, 1.0 :: Double) gen) cat where
timeout = 47 -- give up
genTrees ds0 cat =
let (ds,ds2) = splitAt (timeout+1) ds0 -- for time out, else ds
(t,k) = genTree ds cat
in (if k>timeout then id else (t:))
(genTrees ds2 cat) -- else (drop k ds)
genTree rs = gett rs where
gett ds cid | cid == mkCId "String" = (Lit (LStr "foo"), 1)
gett ds cid | cid == mkCId "Int" = (Lit (LInt 12345), 1)
gett [] _ = (Lit (LStr "TIMEOUT"), 1) ----
gett ds cat = case fns cat of
[] -> (Meta 0,1)
fs -> let
d:ds2 = ds
(f,args) = getf d fs
(ts,k) = getts ds2 args
in (Fun f ts, k+1)
getf d fs = let lg = (length fs) in
fs !! (floor (d * fromIntegral lg))
getts ds cats = case cats of
c:cs -> let
(t, k) = gett ds c
(ts,ks) = getts (drop k ds) cs
in (t:ts, k + ks)
_ -> ([],0)
fns cat = [(f,(fst (catSkeleton ty))) | (f,ty) <- functionsToCat pgf cat]
{-
-- brute-force parsing method; only returns the first result
-- note: you cannot throw away rules with unknown words from the grammar
-- because it is not known which field in each rule may match the input
searchParse :: Int -> PGF -> CId -> [String] -> [Exp]
searchParse i pgf cat ws = [t | t <- gen, s <- lins t, words s == ws] where
gen = take i $ generate pgf cat
lins t = [linearize pgf lang t | lang <- cncnames pgf]
-}
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