[m-users.] A predicate taking a lists of predicates as input?

[Volker Wysk]

Am Mittwoch, dem 24.09.2025 um 18:09 +0200 schrieb Tomas By:
> On Wed, 24 Sep 2025 17:32:05 +0200, Anders Lundstedt wrote:
> > Thanks everyone for the help! Now another, related, issue.
> 
> 
> So `?' applies a list of rules, and then you are nesting them?
> 
> First, you could look at list:all_true/1 and related preds.
> 
> Then it might be better if you try to explain what it is all about.
> 
> If you want to parse a limited, static formalism, like some variant of
> predicate logic, then DCG may not be the best solution.

DCGs are just a handy syntax for predicates with a state variable at the end
of the arguments. When you have that in mind, it's doesn't matter if you use
DCGs or state variables explicitly. 

> 
> If you really want to use DCG, ie experiment with the grammar and have
> something that is easy to work with, then just declare everything
> nondet and be done with it.
> 
> You just need a top-level call that handles the nondeterminism (calls
> solution/2 and picks the first in the list of results).

I don't think that's a good idea, for various reasons.

Cheers,
Volker