[Haskell-cafe] ∀ lexing in ghc and ghci

[Daniel Fischer]

Am Freitag 18 September 2009 03:31:13 schrieb Sean McLaughlin:
> Hi,
>   I'm getting different behavior in ghci and ghc with the identifier ∀.  In
> ghc I need
> to wrap it with parens, as in
>
> > (∀) :: Var -> Base -> Formula -> Formula
> > (∀) = All
>
> In ghci, I get an error this way
>
> Formula.lhs:112:2:
>     Invalid type signature
>
> In ghci I can do
>
> > ∀ :: Var -> Base -> Formula -> Formula
> > ∀ = All
>
> fine.  But then ghc complains.  What's going on here?

Very odd:

GHCi, version 6.10.3: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer ... linking ... done.
Loading package base ... linking ... done.
Prelude> let ∀ :: Int -> Int -> Int; ∀ x y = x*(y-x)

<interactive>:1:4: parse error on input `∀'
Prelude> let (∀) :: Int -> Int -> Int; x ∀ y = x*(y-x)
Prelude> 3 ∀ 5
6

Maybe your encodings aren't UTF8?

>
> Thanks!
>
> Sean