[antlr-interest] new action syntax proposal
Kay Roepke
kroepke at classdump.org
Fri Jul 13 17:24:37 PDT 2007
On Jul 14, 2007, at 2:04 AM, Gavin Lambert wrote:
> Well, the last I recall ANTLR didn't handle nested {}s anyway,
> meaning that if you wanted to use them you had to use \{ and \}.
> So that would look different, and wouldn't be a problem.
No, curlies are alright.
> Or am I thinking of nested []s for parameters? Or possibly I'm
> just going mad :)
The thing that cropped up a week or so ago were the []s inside
parameters/return values. Things like
rule returns [String[] ary]
: stuff ;
> Anyway, another option could be to use a magic prefix symbol. @
> {...} springs to mind for some reason, though I don't know why ;)
> {Maybe it's from literal strings in C#.]
mmh. I think the delimiters should look like 'always' a bit. It's bit
undefined what 'always' looks like, but it should be (1) easily
recognizable, and (2) consistent.
Sort of like {} means action and {}? means semantic (=code)
predicate. {}! is not really good, since it fails rule 1. Doubling
the curlies satisfies both rules, with caveat I pointed out.
It should definitely be something with curlies, since they are
actions. Maybe it's time to look for an Unicode character that's
describe as 'always'?
;)
cheers,
-k
--
Kay Röpke
http://classdump.org/
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