Files
gf-core/src/compiler/GF/Command/TreeOperations.hs

33 lines
994 B
Haskell

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 and computing",
Right $ \f -> map (compute pgf . EApp (EFun 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