Re: Detecting the presence of a pattern in an atom

Hi all,

the following DCG nonterminal, known from the documentation of
library(pio) by Ulrich Neumerkel, may also help for such use cases:

   ... --> [] ; [_], ... .

With Jeff's definition of upper_alpha_string//1, we can write:

   in_parentheses(String, Atom) :-
           phrase((...,"(",upper_alpha_string(Codes),")",...), String),
           atom_codes(Atom, Codes).

Example:

   %?- in_parentheses("acme ltd (HELLO) 123 (TEST)", X).
   %@ X = 'HELLO' ;
   %@ X = 'TEST' ;
   %@ false.

All the best,
Markus