45 lines
1.2 KiB
Elm
45 lines
1.2 KiB
Elm
import String exposing (reverse, length)
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import Html exposing (Html, Attribute, text, div, input)
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import Html.Attributes exposing (placeholder, value, style)
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import Html.Events exposing (on, targetValue)
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import Html.App exposing (beginnerProgram)
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-- The following function (copied from Haskell) satisfies the
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-- rosettacode task description.
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is_palindrome x = x == reverse x
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-- The remainder of the code demonstrates the use of the function
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-- in a complete Elm program.
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main = beginnerProgram { model = "" , view = view , update = update }
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update newStr oldStr = newStr
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view : String -> Html String
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view candidate =
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div []
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([ input
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[ placeholder "Enter a string to check."
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, value candidate
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, on "input" targetValue
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, myStyle
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]
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[]
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] ++
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[ let testResult =
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is_palindrome candidate
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statement =
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if testResult then "PALINDROME!" else "not a palindrome"
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in div [ myStyle] [text statement]
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])
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myStyle : Attribute msg
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myStyle =
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style
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[ ("width", "100%")
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, ("height", "20px")
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, ("padding", "5px 0 0 5px")
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, ("font-size", "1em")
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, ("text-align", "left")
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]
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