On 08/01/06, Bruno Oliveira <[EMAIL PROTECTED]> wrote:
> On 08 Jan 2006 16:37:47 +0100, Peter Simons wrote:
>
> >Bruno Oliveira writes:
>
> > >> class Foo o where
> > >> (:+) :: o -> o -> o
>
> >The Haskell report specifies in section "2.4 Identifiers and
> >Operators":
>
> > An operator symbol starting with a colon is a constructor.
>
> >Think of ':' as a character that is interpreted as "uppercase";
> >you can't use it to start a function or variable name.
>
> Then this declaration should be rejected as invalid, right?
>
> That's why I think this is a parsing bug...
>
> Cheers,
>
> Bruno
Hmm... yeah, it does seem like a parsing bug. The relevant rules from
the report are:
----
topdecl -> ...
| class [scontext =>] tycls tyvar [where cdecls]
...
cdecls -> { cdecl1 ; ... ; cdecln } (n>=0)
cdecl -> gendecl
| ...
gendecl -> vars :: [context =>] type (type signature)
| ...
vars -> var1 , ..., varn (n>=1)
var -> varid | ( varsym )
varsym -> ( symbol {symbol | :})<reservedop | dashes>
----
So it should not be permitting a type declaration for something
starting with a colon, since symbol does not match colon.
_______________________________________________
Haskell mailing list
Haskell@haskell.org
http://www.haskell.org/mailman/listinfo/haskell
