I was thinking that a derived grammar would be unambiguous about the output format, but you would reuse many useful grammar rules.

Instead of $a := (\d+), write  $a := <number_token> where number_token is itself defined as you show, or more complex such as (0|0[xX])\d+. Then, a derived grammar would override number_token to be something that formats, as opposed to something that accepts flexible input. Some standard mechanism would say "here is the string to be emitted" within the {} block of the rule.

Terminals, by definition, would need to contain code to format the output. Nonterminals just state the arrangement of terminals, and in the absence of alternation and repitition (push that down to a lower level rule) would be used as-is.

—John

In reply to Re: Re: Using Perl6 patterns/grammar definition for <I>output</I>? by John M. Dlugosz
in thread Using Perl6 patterns/grammar definition for 'output'? by John M. Dlugosz

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