Contents

module BracketPush exposing (isPaired)

import Dict exposing (Dict)
import List
import String


isPaired : String -> Bool
isPaired input =
    let
        onlyBrackets =
            String.filter (flip List.member bracketList)

        tryMatching bracket visited =
            case visited of
                [] ->
                    bracket :: visited

                top :: visited ->
                    if isPairMatch top bracket then
                        visited
                    else
                        bracket :: top :: visited

        isPairMatch prev current =
            case Dict.get prev bracketDict of
                Nothing ->
                    False

                Just rightBracket ->
                    current == rightBracket
    in
    input
        |> onlyBrackets
        |> String.foldl tryMatching []
        |> List.isEmpty


bracketList : List Char
bracketList =
    [ '{', '}', '[', ']', '(', ')' ]


bracketDict : Dict Char Char
bracketDict =
    Dict.fromList
        [ ( '{', '}' )
        , ( '[', ']' )
        , ( '(', ')' )
        ]

Version data entries

26 entries across 26 versions & 1 rubygems

Version	Path
trackler-2.2.1.180	tracks/elm/exercises/bracket-push/BracketPush.example.elm
trackler-2.2.1.179	tracks/elm/exercises/bracket-push/BracketPush.example.elm
trackler-2.2.1.178	tracks/elm/exercises/bracket-push/BracketPush.example.elm
trackler-2.2.1.177	tracks/elm/exercises/bracket-push/BracketPush.example.elm
trackler-2.2.1.176	tracks/elm/exercises/bracket-push/BracketPush.example.elm
trackler-2.2.1.175	tracks/elm/exercises/bracket-push/BracketPush.example.elm
trackler-2.2.1.174	tracks/elm/exercises/bracket-push/BracketPush.example.elm
trackler-2.2.1.173	tracks/elm/exercises/bracket-push/BracketPush.example.elm
trackler-2.2.1.172	tracks/elm/exercises/bracket-push/BracketPush.example.elm
trackler-2.2.1.171	tracks/elm/exercises/bracket-push/BracketPush.example.elm
trackler-2.2.1.170	tracks/elm/exercises/bracket-push/BracketPush.example.elm
trackler-2.2.1.169	tracks/elm/exercises/bracket-push/BracketPush.example.elm
trackler-2.2.1.167	tracks/elm/exercises/bracket-push/BracketPush.example.elm
trackler-2.2.1.166	tracks/elm/exercises/bracket-push/BracketPush.example.elm
trackler-2.2.1.165	tracks/elm/exercises/bracket-push/BracketPush.example.elm
trackler-2.2.1.164	tracks/elm/exercises/bracket-push/BracketPush.example.elm
trackler-2.2.1.163	tracks/elm/exercises/bracket-push/BracketPush.example.elm
trackler-2.2.1.162	tracks/elm/exercises/bracket-push/BracketPush.example.elm
trackler-2.2.1.161	tracks/elm/exercises/bracket-push/BracketPush.example.elm
trackler-2.2.1.160	tracks/elm/exercises/bracket-push/BracketPush.example.elm