hledger/Utils.hs
Simon Michael e7d36bb40e cleanup
2007-07-02 23:54:17 +00:00

64 lines
1.6 KiB
Haskell

-- standard imports and utilities
module Utils (
module Utils,
module Data.List,
module Data.Tree,
module Text.Printf,
module Text.Regex,
module Debug.Trace,
module Test.QuickCheck,
module Test.HUnit
)
where
import Data.List
import Data.Tree
import Text.Printf
import Text.Regex
import Debug.Trace
import Test.QuickCheck hiding (test, Testable)
import Test.HUnit
-- lists
splitAtElement :: Eq a => a -> [a] -> [[a]]
splitAtElement e l =
case dropWhile (e==) l of
[] -> []
l' -> first : splitAtElement e rest
where
(first,rest) = break (e==) l'
-- trees
-- aliases
root = rootLabel
branches = subForest
-- remove all nodes past a certain depth
treeprune :: Int -> Tree a -> Tree a
treeprune 0 t = Node (root t) []
treeprune d t = Node (root t) (map (treeprune $ d-1) $ branches t)
-- apply f to all tree nodes
treemap :: (a -> b) -> Tree a -> Tree b
treemap f t = Node (f $ root t) (map (treemap f) $ branches t)
-- remove all subtrees whose nodes do not fulfill predicate
treefilter :: (a -> Bool) -> Tree a -> Tree a
treefilter f t = Node
(root t)
(map (treefilter f) $ filter (treeany f) $ branches t)
-- is predicate true in any node of tree ?
treeany :: (a -> Bool) -> Tree a -> Bool
treeany f t = (f $ root t) || (any (treeany f) $ branches t)
-- treedrop -- remove the leaves which do fulfill predicate.
-- treedropall -- do this repeatedly.
-- debugging
strace a = trace (show a) a -- trace a showable expression