[antlr-interest] still more => wars ;)
Terence Parr
parrt at cs.usfca.edu
Thu Dec 8 14:53:52 PST 2005
On Dec 8, 2005, at 2:45 PM, Chris Black wrote:
> Terence Parr wrote:
>
>> Ok, so I not overjoyed with what you guys propose either ;)
>> Adding random new symbols is probably not the answer. :)
>>
>> How about the following which is identical to what ANTLR v2 does.
>> To get hoisted preds though you'll need the '=>' not '?'.
>>
>> (...) => syntactic predicate
>> {...} => _hoisting_ disambiguating semantic predicate
>> {...}? gated semantic predicate
>
> Would (...)? syntax still mean the same thing it does in ANTLR 2.7.x?
Yes.
> If so, I'm cool with the above proposed syntax, although I'd prefer
> {...} ?=> for gated semantic predicate. That way "=>" always means
> a predicate of some sort.
So, you'd vote for:
(...) => syntactic predicate
{...} => _hoisting_ disambiguating semantic predicate
{...}? => gated semantic predicate
Hmm...the two kinds of sem preds are pretty similar this way. I do
like the => implies predicate though. I wonder what we could do to
indicate gated. Loring's original suggestion was
which is verbose but these are not used much and it's clear what we
mean w/o new syntax. We could then do
(...) => syntactic predicate
{...}? _hoisting_ disambiguating semantic predicate
( {...}? ) => gated semantic predicate
leaving everything the way they are now but adding the last syntax.
Ter
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