Tree datastructures: Difference between revisions
m
→{{header|Haskell}}: Added output of [(Int, String] list to Data.Tree variant.
m (→{{header|Haskell}}: Narrowed one type in the Data.Tree variant.) |
m (→{{header|Haskell}}: Added output of [(Int, String] list to Data.Tree variant.) |
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import Data.List (find)
import Data.Tree (Forest, Tree (..), drawTree)
-------- MAPPINGS BETWEEN INDENTED LINES AND TREES -------
forestFromNestLevels :: [(Int, String)] -> Forest String
forestFromNestLevels = go
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uncurry (:) $
bimap (Node v . go) go (span ((n <) . fst) xs)
indentLevelsFromLines :: [String] -> [(Int, String)]
indentLevelsFromLines xs =
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indentUnit = maybe 1 fst (find ((0 <) . fst) pairs)
in first (`div` indentUnit) <$> pairs
outlineFromForest ::
(String -> a -> String) ->
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(subForest node >>= go ((<>) tabString indent))
in unlines $ forest >>= go ""
-------------------------- TESTS -------------------------
main :: IO ()
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putStrLn "Tree representation parsed directly:\n"
putStrLn $ drawTree $ Node "" nativeForest
let levelPairs = indentLevelsFromLines test
putStrLn "Trees from indented text:\n"▼
putStrLn "\n[(Level, Text)] list from lines:\n"
mapM_ print levelPairs
let trees =
forestFromNestLevels $
putStrLn $ drawTree $ Node "" trees
putStrLn "Indented text from trees:\n"
putStrLn $ outlineFromForest (<>) " " trees
test :: [String]
test =
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" irregular"
]
nativeForest :: Forest String
nativeForest =
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`- irregular
[(Level, Text)] list from lines:
(0,"RosettaCode")
(1,"rocks")
(2,"code")
(2,"comparison")
(2,"wiki")
(1,"mocks")
(2,"trolling")
(0,"Some lists")
(3,"may")
(2,"be")
(1,"irregular")
Trees from indented text:
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