[antlr-interest] new action syntax proposal

[Terence Parr]

Hi,

Actions are not executed during backtracking as we cannot undo  
stateful actions.  The problem is that some semantic predicates that  
test, for example, the symbol table rely on actions updating the  
symbol table during backtracking.  I propose {...} stay same as an  
action but {{...}} (double curlies) implies always execute even when  
backtracking.

Counterproposals?

Ter