Elm - Handling the Basics(partially applied function, currying, List.filter, anonymous functions)

Seven More Languages
in Seven Weeks

開発環境

• OS X El Capitan - Apple (OS)
• Emacs (Text Editor)
• Elm (プログラミング言語)

Seven More Languages in Seven Weeks (Bruce Tate (著)、Ian Dees (著)、Frederic Daoud (著)、Jack Moffitt (著)、Pragmatic Bookshelf)のChapter 3(Elm)、Day 1(Handling the Basics)、Do (Medium)(No. 3034).を取り組んでみる。

Do (Medium)(No. 3034)

入出力結果(Emacs, Terminal, elm repl)

$ elm-repl
---- elm repl 0.16.0 -----------------------------------------------------------
 :help for help, :exit to exit, more at <https://github.com/elm-lang/elm-repl>
--------------------------------------------------------------------------------
> multiply a b = a * b
<function> : number -> number -> number
> multiply 6 8
48 : number
> multiplyX = multiply 6
<function> : number -> number
> multiplyX 8
48 : number
> multiplyXY = multiplyX 8
48 : number
> multiplyXY
48 : number
> List.filter
<function> : (a -> Bool) -> List a -> List a
> personRecords = [{name="elm1", age=16, address={country="Japan", state="Tokyo"}}, {name="elm2", age=15, address={country="Japan", state="Tokyo"}},  {name="elm3", age=17, address={country="Japan", state="Tokyo"}}, {name="elm4", age=18, address={country="Japan", state="Tokyo"}}, {name="elm5", age=10, address={country="Japan", state="Tokyo"}}]
[{ name = "elm1", age = 16, address = { country = "Japan", state = "Tokyo" } },{ name = "elm2", age = 15, address = { country = "Japan", state = "Tokyo" } },{ name = "elm3", age = 17, address = { country = "Japan", state = "Tokyo" } },{ name = "elm4", age = 18, address = { country = "Japan", state = "Tokyo" } },{ name = "elm5", age = 10, address = { country = "Japan", state = "Tokyo" } }]
    : List
        { address : { country : String, state : String }
        , age : number
        , name : String
        }
> List.filter (\x -> x.age > 16) personRecords
[{ name = "elm3", age = 17, address = { country = "Japan", state = "Tokyo" } },{ name = "elm4", age = 18, address = { country = "Japan", state = "Tokyo" } }]
    : List
        { address : { country : String, state : String }
        , name : String
        , age : number
        }
> :exit
$