forked from GitHub/gf-core
51 lines
1.7 KiB
Haskell
51 lines
1.7 KiB
Haskell
module GF.Command.TreeOperations (
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treeOp,
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allTreeOps,
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treeChunks
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) where
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import PGF2(Expr,PGF,Fun,compute,mkApp,unApp,unapply,unMeta,exprSize,exprFunctions)
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import Data.List
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type TreeOp = [Expr] -> [Expr]
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treeOp :: PGF -> String -> Maybe (Either TreeOp (Fun -> TreeOp))
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treeOp pgf f = fmap snd $ lookup f $ allTreeOps pgf
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allTreeOps :: PGF -> [(String,(String,Either TreeOp (Fun -> TreeOp)))]
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allTreeOps pgf = [
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("compute",("compute by using semantic definitions (def)",
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Left $ map (compute pgf))),
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("largest",("sort trees from largest to smallest, in number of nodes",
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Left $ largest)),
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("nub",("remove duplicate trees",
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Left $ nub)),
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("smallest",("sort trees from smallest to largest, in number of nodes",
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Left $ smallest)),
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("subtrees",("return all fully applied subtrees (stopping at abstractions), by default sorted from the largest",
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Left $ concatMap subtrees)),
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("funs",("return all fun functions appearing in the tree, with duplications",
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Left $ \es -> [mkApp f [] | e <- es, f <- exprFunctions e]))
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]
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largest :: [Expr] -> [Expr]
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largest = reverse . smallest
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smallest :: [Expr] -> [Expr]
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smallest = sortBy (\t u -> compare (exprSize t) (exprSize u))
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treeChunks :: Expr -> [Expr]
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treeChunks = snd . cks where
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cks t =
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case unapply t of
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(t, ts) -> case unMeta t of
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Just _ -> (False,concatMap (snd . cks) ts)
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Nothing -> case unzip (map cks ts) of
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(bs,_) | and bs -> (True, [t])
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(_,cts) -> (False,concat cts)
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subtrees :: Expr -> [Expr]
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subtrees t = t : case unApp t of
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Just (f,ts) -> concatMap subtrees ts
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_ -> [] -- don't go under abstractions
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