[antlr-interest] ANTLRWorks "synpredNN_MyGrammar" labels

Ben Gillis wbgillis at gmail.com
Sat Nov 1 14:25:00 PDT 2008

...but, this is the exact-same rules, same order in the grammar file; just a 
subset of the grammar where these same rules do display the synpred.
Why ANTLR needs to backtrack in one and not the other I'm not clear on.
(So, back to the Definitive Guide on b/t'ing for clues will help?)

----- Original Message ----- 
From: "Terence Parr" <parrt at cs.usfca.edu>
To: "Ben Gillis" <wbgillis at gmail.com>
Cc: <antlr-interest at antlr.org>
Sent: Saturday, November 01, 2008 4:14 PM
Subject: Re: [antlr-interest] ANTLRWorks "synpredNN_MyGrammar" labels

> On Nov 1, 2008, at 2:11 PM, Ben Gillis wrote:
>> OK...thanks. :-)
>> So, why are they present in some ANTLRWorks Syntax Diagrams, but not  in 
>> others?  (Exact-same grammar rules, the smaller, trimmed down  grammars 
>> do not have them...but, beyond being the exact-same rules,  sub-rules, 
>> etc. I don't know why/what else in the grammar would  determine when 
>> they're displayed).
> ANTLR only backtracks when it can't avoid it. Even if you specify 
> backtracking, ANTLR does it when it's necessary only.
> T 

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