[Haskell] Re: comment vs varsym

[Taral]

On 12/12/05, Simon Marlow <simonmar at microsoft.com> wrote:
> This looks like a mistake in the syntax.  I think GHC is following the
> letter of the spec, but I also think that the intended behaviour was to
> admit --: as a varsym, i.e. Hugs' behaviour.

I agree. I suggest modifying the "comment" production to read:

comment -> dashes [ any<symbol | :> {any}] newline

> I'm not aware of maximal munch being applied only to non-whitespace;
> does it say so anywhere in the report?

Yes, from section 2.2:

> Lexical analysis should use the "maximal munch" rule: at each point,
> the longest possible lexeme satisfying the lexeme production is read.

Since the "whitespace" production is not included as part of the
"lexeme" production, maximal munch must not apply to comments.

--
Taral <taralx at gmail.com>
"Computer science is no more about computers than astronomy is about
telescopes."
    -- Edsger Dijkstra