Comment Syntax

Creighton Hogg wchogg at
Wed Feb 1 21:26:26 EST 2006

On Thu, 2 Feb 2006, Henrik Nilsson wrote:

> Hi all,
> To corroborate Wadler's law further.
> Josef wrote:
>  > Oh yes, it does happen that a single line comment begins with a
>  > special symbol. It has happened to me on several occations when using
>  > haddock annotation to my source code. It is all to easy to forget that
>  > extra space. With incomprehensible error messages as a result.
> But might that not just mean that the error messages ought to be
> improved?
> I don't know how hard that would be, but after having played around
> a bit with GHC, the messages I get are either of the type
> "parse error on input '--|'" or of the type "Not in scope: `-->'"
> (followed by lots of other stuff not being in scope etc).
> If this really is a big problem for beginners, it would not seem
> totally infeasible to add some special code that helpfully suggests
> that a space perhaps ought to be inserted?
> Or have you seen significantly worse error messages?

Well, if anecdotal evidence from a real live beginner would 
help, I've never had problems with the comments.
I think I made that mistake once, looked at the line it 
failed on, and added the space.

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