[antlr-interest] Antlr 3 syntax question

[Terence Parr]

On Apr 27, 2006, at 4:01 AM, shmuel siegel wrote:

> I would also like to understand the usage of alternatives and  
> parenthesis. According to AntlrWorks, the following rule has 4  
> alternatives consistent with the visual layout of this rule. The  
> second and third alternatives are identical. My question is "Why is  
> there an implied parenthesis around the second alternative?". In  
> other words, does sequencing of tokens always take precedence to  
> alternatives?
>
> levelExpr     :  # one
>        INT
>    | # two
>         '@level' '(' 'offset' '=' INT ')'
>    | # three
>         ('@level' '(' 'offset' '=' INT ')' )
>    | # four
>    ;

See annotations.  4 alts.  #alts = #pipes + 1.

The '|' binds most loosely.  Every grammar tool I've seen does this I  
think...does it seem weird or different from v2?

Ter