Luke Palmer wrote:
> Also, if this is going to be an explanation rather than just a picture,
> I suggest you go with Perl's usual versatile power, and store the
> operators in a declarative data source.
>
> grammar RPN {
> my @operator = << + - * / >>;
>
> rule input { <line>* }
> rule line { <exp>? \n }
> rule exp :w{ <NUM> | <@operator> }
>
> rule NUM { \d+ }
This becomes too weak.
rule exp :w{ <NUM> | <exp> <exp> <@binary_operator> }
is stronger.
But it involves left-recursion, so it's typically better adapted to
yacc-like parser generators. Probably not to P6 rules...
