[antlr-interest] new action syntax proposal

[Diehl, Matthew J]

> Terence Parr wrote:
> > I propose {...} stay same as an
> > action but {{...}} (double curlies) implies always execute even when
> > backtracking.
> > 
> > Counterproposals?
> 
> I'd vote for "@always { ... }" or a similar keyword: exploit existing
> syntax, use explicit keywords instead of adding more 'magic' 
> characters.

It's always nice to use already existing syntax, but if it was
@always{...}, then could it be used anywhere within the rule?  
It would be nice if it could be used within the rule (with {{...}} ) as
well.  So I vote for the {{...}} (as if my vote matters, lol...more like
my preference and not a vote).
There are already several other languages that use double curlies (like
System Verilog), so it shouldn't be too bad.  That, and also people
aren't
going to accidentally type {{ unless they already know it is a 'magic' 
character.  Only those who WANT to use it will add it (it's not like the
ever-so-common naming a parser/lexer rule after a reserved keyword).

Matt