Excellent bikeshedding opportunity! Frontend syntax for pattern synonym types
Dr. ERDI Gergo
gergo at erdi.hu
Sun Dec 22 16:44:29 UTC 2013
On Sun, 22 Dec 2013, Jacques Carette wrote:
> pattern P :: (Show t) => ( (Num t, Eq b) => b -> T t )
> perhaps? Given 'Show t', you get what's on the rhs of the first => ?
I like this one; in fact, I originally wanted to go with something like
that. But unfortunately, this type is already valid and is
parsed simply as (Show t, Num t, Eq b) => b -> T t by GHC:
Prelude> :t undefined :: (Show t) => ((Num t, Eq b) => b -> Maybe t)
undefined :: (Show t) => ((Num t, Eq b) => b -> Maybe t)
:: (Eq b, Num t, Show t) => b -> Maybe t
.--= ULLA! =-----------------.
\ http://gergo.erdi.hu \
`---= gergo at erdi.hu =-------'
A pessimist sees the glass half empty, the optimist sees it half full and the blind can't see shit
More information about the Glasgow-haskell-users