Add support for per-problem fact libraries

Each fact library is loaded at most once, so different problems can
share the same library (e.g. family-relation problems).

1 files changed, 5 insertions, 2 deletions

diff --git a/prolog/engine.py b/prolog/engine.py
index 8ad8bfa..c859b67 100644
--- a/prolog/engine.py
+++ b/prolog/engine.py
@@ -117,8 +117,7 @@ class PrologEngine(object):
         self.answers = {}
 
     # Loads the correct solution [code] to problem [pid].
-    # TODO handle library loading.
-    def load_solution(self, pid, code):
+    def load_solution(self, pid, code, facts=None):
         module = 'solution{}'.format(pid)
 
         fid = PL_open_foreign_frame()
@@ -126,6 +125,10 @@ class PrologEngine(object):
         for rule in prolog.util.split(code):
             self.call('assertz/1', [Term('{}:({})'.format(module, rule))])
             predicates.add('{}:{}'.format(module, self.predicate_indicator(rule)))
+        if facts:
+            for rule in prolog.util.split(facts):
+                self.call('assertz/1', [Term(rule)])
+                predicates.add(self.predicate_indicator(rule))
         self.call('compile_predicates/1', [Term([Term(p) for p in predicates])])
         PL_discard_foreign_frame(fid)