Need help splitting out a utility module [AOC day 2 spoilers]

[librarianmage]

Hi,

I am working on making a utility module for my Advent of Code scripts, but while everything works when I keep it all in one file, splitting it out gives me the following error:

?- input(I), solutionA(I, S).
   error(existence_error(procedure,game/3),game/3).

Am I misunderstanding things?

day02.prolog.txt
util.prolog.txt

[librarianmage]

It appears that util.prolog "can't see" the dcgs in day02.prolog. Is there a way I can fix that?

[aarroyoc]

You need to add:

:- meta_predicate parse_lines(:, ?, ?, ?).

after the module declaration in util.prolog. This is required because otherwise the parse_lines//2 predicate receives just an atom that cannot resolve, because we're not importing the day02 module in util. Modules are like namespaces, so in order to see it, we need to attach the module name in front of the predicate. :- meta_predicate allows us to let the Prolog system do that for us for a specific argument in a call.

[librarianmage]

Works perfectly, thanks!

[triska]

Thank you a lot for posting this! It is nice to see the first instances of clpz:monotonic in interesting programs!

One small thing I noticed in the code: Maybe the predicate (#=)/3 which is provided by library(clpz) could be useful, since it can be used instead of clpz_reif/2:

?- #=(#X, 1, T).
   T = false, clpz:(X in inf..0\/2..sup)
;  X = 1, T = true.

Thanks to your example, I noticed that (#=)/3 currently does not work in the monotonic execution mode, so your code would be the first such use ever! I have filed #2194 to make it work in this mode.

[librarianmage]

Thank you for the kind words! I still feel very inexperienced, so it's good to know that I'm not making glaring mistakes :)