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https://github.com/GrammaticalFramework/gf-core.git
synced 2026-05-09 03:02:50 -06:00
93 lines
2.5 KiB
Haskell
93 lines
2.5 KiB
Haskell
module Generate where
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import GFC
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import LookAbs
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import PrGrammar
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import Macros
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import Operations
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import List
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-- Generate all trees of given category and depth. AR 30/4/2004
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-- (c) Aarne Ranta 2004 under GNU GPL
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--
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-- Purpose: to generate corpora. We use simple types and don't
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-- guarantee the correctness of bindings/dependences.
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-- the main function takes an abstract syntax and returns a list of trees
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-- generateTrees :: GFCGrammar -> Cat -> Int -> Maybe Int -> [Exp]
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generateTrees gr cat n mn = map str2tr $ generate gr' cat' n mn where
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gr' = gr2sgr gr
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cat' = prt $ snd cat
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------------------------------------------
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-- translate grammar to simpler form and generated trees back
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gr2sgr :: GFCGrammar -> SGrammar
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gr2sgr gr = [(trId f, ty') | (f,ty) <- funRulesOf gr, ty' <- trTy ty] where
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trId = prt . snd
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trTy ty = case catSkeleton ty of
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Ok (mcs,mc) -> [(map trCat mcs, trCat mc)]
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_ -> []
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trCat (m,c) = prt c ---
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-- str2tr :: STree -> Exp
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str2tr (STr (f,ts)) = mkApp (trId f) (map str2tr ts) where
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trId = cn . zIdent
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------------------------------------------
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-- do the main thing with a simpler data structure
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-- the first Int gives tree depth, the second constrains subtrees
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-- chosen for each branch. A small number, such as 2, is a good choice
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-- if the depth is large (more than 3)
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generate :: SGrammar -> SCat -> Int -> Maybe Int -> [STree]
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generate gr cat i mn = [t | (c,t) <- gen 0 [], c == cat] where
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gen :: Int -> [(SCat,STree)] -> [(SCat,STree)]
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gen n cts = if n==i then cts else
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gen (n+1) (nub [(c,STr (f, xs)) | (f,(cs,c)) <- gr, xs <- args cs cts] ++ cts)
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args :: [SCat] -> [(SCat,STree)] -> [[STree]]
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args cs cts = combinations [constr [t | (k,t) <- cts, k == c] | c <- cs]
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constr = maybe id take mn
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type SGrammar = [SRule]
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type SIdent = String
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type SRule = (SFun,SType)
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type SType = ([SCat],SCat)
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type SCat = SIdent
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type SFun = SIdent
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newtype STree = STr (SFun,[STree]) deriving (Show,Eq)
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------------------------------------------
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-- to test
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prSTree (STr (f,ts)) = f ++ concat (map pr1 ts) where
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pr1 t@(STr (_,ts)) = ' ' : (if null ts then id else prParenth) (prSTree t)
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pSRule :: String -> SRule
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pSRule s = case words s of
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f : _ : cs -> (f,(init cs', last cs'))
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where cs' = [cs !! i | i <- [0,2..length cs - 1]]
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_ -> error $ "not a rule" +++ s
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exSgr = map pSRule [
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"Pred : NP -> VP -> S"
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,"Compl : TV -> NP -> VP"
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,"PredVV : VV -> VP -> VP"
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,"DefCN : CN -> NP"
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,"ModCN : AP -> CN -> CN"
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,"john : NP"
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,"walk : VP"
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,"love : TV"
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,"try : VV"
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,"girl : CN"
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,"big : AP"
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]
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