module GF.Command.TreeOperations ( treeOp, allTreeOps ) where import PGF import PGF.Data import Data.List type TreeOp = [Expr] -> [Expr] treeOp :: PGF -> String -> Maybe (Either TreeOp (CId -> TreeOp)) treeOp pgf f = fmap snd $ lookup f $ allTreeOps pgf allTreeOps :: PGF -> [(String,(String,Either TreeOp (CId -> TreeOp)))] allTreeOps pgf = [ ("compute",("compute by using semantic definitions (def)", Left $ map (compute pgf))), ("transfer",("syntactic transfer by applying function, recursively in subtrees", Right $ \f -> map (transfer pgf f))), ("paraphrase",("paraphrase by using semantic definitions (def)", Left $ nub . concatMap (paraphrase pgf))), ("smallest",("sort trees from smallest to largest, in number of nodes", Left $ smallest)) ] smallest :: [Expr] -> [Expr] smallest = sortBy (\t u -> compare (size t) (size u)) where size t = case t of EAbs _ _ e -> size e + 1 EApp e1 e2 -> size e1 + size e2 + 1 _ -> 1 --- simple-minded transfer; should use PGF.Expr.match transfer :: PGF -> CId -> Expr -> Expr transfer pgf f e = case transf e of v | v /= appf e -> v _ -> case e of EApp g a -> EApp (transfer pgf f g) (transfer pgf f a) _ -> e where appf = EApp (EFun f) transf = compute pgf . appf