Re: GADTs in the wild

[Christian Maeder]

Am 14.08.2012 14:48, schrieb Felipe Almeida Lessa:

   data AccessToken kind where
       UserAccessToken :: UserId -> AccessTokenData -> UTCTime ->
AccessToken UserKind
       AppAccessToken  :: AccessTokenData -> AccessToken AppKind

   data UserKind
   data AppKind

(Yes, that could be a data kind!)  And for convenience we also export
some type synonyms:

   type UserAccessToken = AccessToken UserKind
   type AppAccessToken = AccessToken AppKind

Why not use plain h98?

  data UserAccessToken = UserAccessToken UserId AccessTokenData UTCTime
  data AppAccessToken = AppAccessToken AccessTokenData

  type AccessToken = Either UserAccessToken AppAccessToken

C.

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