```ruby
class ElmPlatform < Cask
  version '0.12.3'
  sha256 '155569928a868095b2b27e705f2904496918f28fcb59990ff4449ca4aace330f'

  url 'https://dl.dropboxusercontent.com/s/qfz9n90jszcxa5q/Elm-Platform-0.12.3.pkg'
  homepage 'http://www.elm-lang.org'

  pkg 'Elm-Platform-0.12.3.pkg'
  uninstall :pkgutil => [
                         'org.elm-lang.bin.pkg',
                         'org.elm-lang.share.pkg'
                        ]
end
```

Update Elm Platform to 0.13
user
```ruby
class ElmPlatform < Cask
  version '0.13'
  sha256 '98ec14efd54b19c9a90c9b9103d1fed4583df927abf6d3a618ef38a80b9a3d41'

  url "http://install.elm-lang.org/Elm-Platform-#{version}.pkg"
  homepage 'http://www.elm-lang.org'

  pkg "Elm-Platform-#{version}.pkg"
  uninstall :pkgutil => 'org.elm-lang.*',
            :delete => '/usr/local/share/elm'
end
```
assistant