Tree datastructures: Difference between revisions

import Data.List (find)

import Data.Tree (Forest, Tree (..), drawTree)

-------- MAPPINGS BETWEEN INDENTED LINES AND TREES -------

forestFromNestLevels = go

where

uncurry (:) $

bimap (Node v . go) go (span ((n <) . fst) xs)

indentLevelsFromLines :: [String] -> [(Int, String)]

indentLevelsFromLines xs =

indentUnit = maybe 1 fst (find ((0 <) . fst) pairs)

in first (`div` indentUnit) <$> pairs

outlineFromForest ::

(String -> a -> String) ->

(subForest node >>= go ((<>) tabString indent))

in unlines $ forest >>= go ""

-------------------------- TESTS -------------------------

main :: IO ()

putStrLn "Tree representation parsed directly:\n"

putStrLn $ drawTree $ Node "" nativeForest

putStrLn "Trees from indented text:\n"

let trees =

indentLevelsFromLines test

putStrLn $ drawTree $ Node "" trees

putStrLn "Indented text from trees:\n"

putStrLn $ outlineFromForest (<>) " " trees

test :: [String]

test =

" irregular"

]

nativeForest :: Forest String

nativeForest =