[Haskell-cafe] ByteString in patterns

Don Stewart dons at galois.com
Tue Mar 10 19:43:31 EDT 2009

> Don Stewart ha scritto:
>> manlio_perillo:
>>> Hi.
>>> Using normal String type I can define a pattern like:
>>>> let foo "baz" = 777
>>>> foo "baz"
>>> 777
>>> But if I want to use ByteString, what should I do?
>>> This seems impossible, since ByteString data constructor is not available.
>> -XOverloadedStrings
> Perfect, thanks.
> Is this supported by other Haskell implementations, or planned for Haskell'?

Not as far as I know. It was added to GHC just over 2 years ago,


and isn't terribly widely used. Probably ByteString literals are the
current main use (along with interesting EDSL applications, which was
the original motivation afaik). 

-- Don

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