Re: FYI: default %printer/%destructor

[Paul Eggert]

"Joel E. Denny" <address@hidden> writes:

> Sorry, I have no experience with ML.  Would you should me how this might 
> look in a Bison rule?

Not offhand.  C isn't ML, and we'd have to construct types or
something like that.  It'd take some thinking.  But the basic idea is
that the EBNF X* has type "list of whatever X returns", and X? maps to
"either an X-type value, or a null pointer".

> Maybe it's just me, but I prefer Hans' suggestion:
>
>   exp/sum: exp/term1 '+' exp/term2
>
> over
>
>   exp#sum: exp#term1 '+' exp#term2
>
> I can't think of any semantic reason to prefer one over the other.  The 
> slash is just a little easier on my eyes.

I think "/" bugs me because it means "or" in ABNF, which is the
standard grammatical notation used in Internet RFCs; see
<http://www.ietf.org/rfc/rfc4234>.  I could live with "/",
I suppose.

> I don't much like the `-' to mean nothing.  I had originally suggested `!' 
> instead, but I found a reason why I don't like it either, and that reason 
> also applies to `-'.  This one post might help you catch up:
>
>   http://lists.gnu.org/archive/html/bison-patches/2006-11/msg00039.html

Sorry, I don't follow the argument there.  How does it apply to "/"
(or "#" or whatever)?