[antlr-interest] ANTLR3.4: help on @init and @after

[Francis ANDRE]

Hi

This parser rule

foo
     returns[Token = null]
@init
{ allowFOO(true); }
@after
{ allowFOO(false); }
:    FOO { l = $FOO; }
;

is translated into this snippet

          allowFOO(true);
         try {
             {
             FOO1=(Lexem)match(input,FOO,FOLLOW_FOO_in_FOO1247); if 
(state.failed) return l;
             if ( state.backtracking==0 ) { l = FOO1; }
             }
             if ( state.backtracking==0 ) { allowFOO(false); }

Why the @after action is conditioned by a backtracking equal to 0, while 
the @init one is not??

FA