Either.coffee

class Nothing
  constructor: () ->

  bind: (f) ->
    @

class Just
  constructor: (b) ->
    @just = b
  bind: (f) ->
    f @just

class Left
  constructor: (a) ->
    @error = a
  bind: (f) ->
    @

class Right
  constructor: (b) ->
    @right = b
  bind: (f) ->
    f @right


r1 = new Right("tanaka")

console.log "case ", r1.right


hontoWaSakao = (name) ->
    new Right("sakao")

eitherRakusu = (name) ->
    if name == "tanaka"
        new Right(name)
    else
        new Left("rakusu jana-i")

killRakusu = (name) ->
    console.log "yahho ^^"


r1
  .bind(hontoWaSakao)
  .bind(eitherRakusu)
  .bind(killRakusu)
  .bind(doNanka1)
  .bind(doNanka2)
  .bind(doNanka3)

console.log "owari"