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4141067428
* Replace Parsec with Megaparsec (see #289) This builds upon PR #289 by @rasendubi * Revert renaming of parseWithState to parseWithCtx * Fix doctests * Update for Megaparsec 5 * Specialize parser to improve performance * Pretty print errors * Swap StateT and ParsecT This is necessary to get the correct backtracking behavior, i.e. discard state changes if the parsing fails.
88 lines
2.7 KiB
Haskell
88 lines
2.7 KiB
Haskell
module Hledger.Utils.Tree where
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-- import Data.Char
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import Data.List (foldl')
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import qualified Data.Map as M
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import Data.Tree
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-- import Text.Megaparsec
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-- import Text.Printf
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import Hledger.Utils.Regex
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-- import Hledger.Utils.UTF8IOCompat (error')
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-- standard tree helpers
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root = rootLabel
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subs = subForest
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branches = subForest
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-- | List just the leaf nodes of a tree
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leaves :: Tree a -> [a]
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leaves (Node v []) = [v]
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leaves (Node _ branches) = concatMap leaves branches
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-- | get the sub-tree rooted at the first (left-most, depth-first) occurrence
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-- of the specified node value
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subtreeat :: Eq a => a -> Tree a -> Maybe (Tree a)
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subtreeat v t
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| root t == v = Just t
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| otherwise = subtreeinforest v $ subs t
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-- | get the sub-tree for the specified node value in the first tree in
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-- forest in which it occurs.
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subtreeinforest :: Eq a => a -> [Tree a] -> Maybe (Tree a)
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subtreeinforest _ [] = Nothing
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subtreeinforest v (t:ts) = case (subtreeat v t) of
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Just t' -> Just t'
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Nothing -> subtreeinforest v ts
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-- | remove all nodes past a certain depth
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treeprune :: Int -> Tree a -> Tree a
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treeprune 0 t = Node (root t) []
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treeprune d t = Node (root t) (map (treeprune $ d-1) $ branches t)
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-- | apply f to all tree nodes
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treemap :: (a -> b) -> Tree a -> Tree b
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treemap f t = Node (f $ root t) (map (treemap f) $ branches t)
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-- | remove all subtrees whose nodes do not fulfill predicate
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treefilter :: (a -> Bool) -> Tree a -> Tree a
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treefilter f t = Node
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(root t)
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(map (treefilter f) $ filter (treeany f) $ branches t)
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-- | is predicate true in any node of tree ?
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treeany :: (a -> Bool) -> Tree a -> Bool
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treeany f t = f (root t) || any (treeany f) (branches t)
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-- treedrop -- remove the leaves which do fulfill predicate.
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-- treedropall -- do this repeatedly.
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-- | show a compact ascii representation of a tree
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showtree :: Show a => Tree a -> String
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showtree = unlines . filter (regexMatches "[^ \\|]") . lines . drawTree . treemap show
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-- | show a compact ascii representation of a forest
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showforest :: Show a => Forest a -> String
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showforest = concatMap showtree
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-- | An efficient-to-build tree suggested by Cale Gibbard, probably
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-- better than accountNameTreeFrom.
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newtype FastTree a = T (M.Map a (FastTree a))
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deriving (Show, Eq, Ord)
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emptyTree = T M.empty
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mergeTrees :: (Ord a) => FastTree a -> FastTree a -> FastTree a
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mergeTrees (T m) (T m') = T (M.unionWith mergeTrees m m')
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treeFromPath :: [a] -> FastTree a
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treeFromPath [] = T M.empty
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treeFromPath (x:xs) = T (M.singleton x (treeFromPath xs))
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treeFromPaths :: (Ord a) => [[a]] -> FastTree a
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treeFromPaths = foldl' mergeTrees emptyTree . map treeFromPath
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