[antlr-interest] Rewriting to Flat Tree Nodes for Associative Multiary Operators

[John B. Brodie]

Greetings! 

On Thursday 02 October 2008 05:23:09 pm Randall R Schulz wrote:
> How might I alter a rule such as this one:
>
> op790Formula
>     :   (op780Formula -> op780Formula)
>         (
>             Or rDisjunct = op790Formula
>         ->  ^(Or $op790Formula $rDisjunct)
>         ) ?
>     ;
>
> (parenthetically:
> op780Formula
>     :   ... // Next higher level of operator precedence (And)
>     ;
> )
>
> which, when given input like this:
>
>         p | q | r | s
>
> produces this sort of tree:
>
>         (Or p (Or q (Or r s)))
>
> so that I instead get this:
>
>         (Or p q r s)

have you tried:

op790Formula : op780Formula ( Or^ op790Formula )? ;

or without recursion:

op790Formula : op780Formula ( Or^ op780Formula )* ;

Hope this helps...
   -jbb