[antlr-interest] Confused about backtracking

[franck102]

This is a 20 years old language with zillions of existing lines of code. If I
can get the parser to work even with an awful lot of backtracking then I can
use it to write a translator that cleans up those kind of stupid idioms...

I think your answer gave me the clue I needed though, apparently
backtracking works between alternatives but consuming or not consuming one
instance of a ( )* construct is not considered an alternative. If I replace
the * construct with tail recursion in my example things work fine - I need
to see if that is something I can do in the real grammar.

So my grammar works fine in this form (rest unchanged):

program
        : statement* EOF
        ;
       
statement
        : ID '=' expr
        | sep
        ;

expr	: ID suffix;
	
suffix	: DOT expr
        | /* nothing */
        ;

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