Bulat Ziganshin <
bulat.ziganshin@...> writes:
> Hello ,
>
> from
http://community.livejournal.com/ru_declarative/54566.html>
> Q: how to see operators precedence in GHCi?
> A:
> Prelude> let showParen = (undefined::[[[[()]]]]->())
> Prelude> showParen $ 2+3*4
> <interactive>:1:12:
> No instance for (Num [[[[()]]]])
> arising from use of `+' at <interactive>:1:12
> Probable fix: add an instance declaration for (Num [[[[()]]]])
> In the second argument of `($)', namely `2 + (3 * 4)'
> In the definition of `it': it = showParen $ (2 + (3 * 4))
Hmm, OK, but not that much quicker than going
Prelude> :info (*)
class (Eq a, Show a) => Num a where
...
(*) :: a -> a -> a
...
-- Defined in GHC.Num
infixl 7 *
Prelude> :info (+)
class (Eq a, Show a) => Num a where
(+) :: a -> a -> a
...
-- Defined in GHC.Num
infixl 6 +
Prelude>
--
Jón Fairbairn
Jon.Fairbairn@...
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