From: Markus <markus@...>
Date: 2004-10-10T02:25:33+09:00
Subject: Re: quality of error messages

On Sat, 2004-10-09 at 10:06, Brian Candler wrote:
> On Sun, Oct 10, 2004 at 01:45:23AM +0900, Markus wrote:
> >      Instead, try to capture what they DON'T do, and store the location
> > to use in the message if there turns out to be a problem.  What don't
> > they do?  
> > 
> >       * They don't 'exdent' beyond the indentation of the line that
> >         started the present construct, except for comments & here docs,
> >         etc. which are already distinguished by the compiler.
> 
> I think you're saying: warn (or note the location of) any line which has
> fewer spaces at the front than the number of spaces which were in front of
> the line which started the current (most deeply nested) construct.
> 
> That seems OK to me; you won't get warnings for
>    def foo
>    line1
>         line2
>      line3
>      end
> 
> but we don't really care, as we're unlikely to have a missing 'end' here.

    Exactly.

> >       * They don't start a nested construct at the same indentation
> >         level of the present construct.
> 
> I do :-( Especially for deeply-nested modules: to keep listings not too
> deeply indented, I write
> 
> module Foo
> module Bar
> class C1
>   def m1
>   end
> end # class C1
> class C2
>   def m2
>   end
> end # class C2
> end # module Bar
> end # module Foo

     Good point.  I have seen stuff like that.

> > I suspect that this would be dirt simple to implement, especially
> > compared to anything that required lookahead.
> 
> You're probably right there. Good enough would do. After all, it's only a
> hint when you get a 'syntax error' at the end of the file.
> 
> Since you've been playing with the parser anyway, perhaps you can have a
> look at it? :-)

     I might.  I'm a little over committed at the moment, but I think I
could sell my boss on the utility of it, in which case, *evil grin* ah,
what to delegate....

     It probably wouldn't be for a few weeks in any case though.

-- Markus