[DGD] Search and replace with parse_string?

[Felix A. Croes]

Krister Svanlund <krister.svanlund at gmail.com> wrote:

> Continuing on the same theme! I've written this grammar that works for
> a color string (such as "RED!") but not for a movement string such as
> "<5" or "^". Movement strings only gives a nil return value and the
> "showthis" function is never called.
>
> mod   = /[!_]/
> move  = /[v<>\^]/
> word  = /[A-Z]+/
> nr    = /[0-9]+/
> color : word
> color : color mod
> movem : move ?showthis
> movem : movem nr

The first production rule defines the start symbol for the grammar,
which in this case is 'color'.  'movem' cannot be reached from there.

Regards,
Felix Croes