On 21 Nov 2006, at 23:41, Joel E. Denny wrote:
The problem is that EBNF is so fundamental, it is important to
find a good
notation of it.
Bison will already need an alternative for {}.
The proposal I made does not use "{ }", except in Bison actions.
There are only so many characters on the
keyboard.
Well, Unicode has some 100000 plus characters, and one might
substitute
poor-mans-ASCII for some of them.
Do you have a specific proposal in mind?
I already gave one: using U+2192 '→', which in ASCII looks like "->".
I suspect that using [] in a grammar to mean optional is not
nearly as
common.
I think it is quite common, in fact.
I don't mean to say it isn't. I mean to say that it's less common
than
(), and we have to pick something.
I think "[ ]" for optional looks good. You seem to have made your
mind about these variables, and want to adapt the other stuff around
it. I wonder if this is wise: if clashes can be avoided that way, the
combination might be cumbersome.
Hans Aberg
