Merge pull request #32 from andrewcropper/variantconstraints

minor correction

Author: andrewcropper

popper/gen2.py

@@ -231,7 +231,10 @@ def build_specialisation_constraint3(self, prog, size=None):
     def find_variants(self, rule):
         head, body = rule
         body_vars = frozenset(x for literal in body for x in literal.arguments if x >= len(head.arguments))
-        subset = range(len(head.arguments), self.settings.max_vars)
+        if max_rule_vars:
+            subset = range(len(head.arguments), len(body_vars | set(head.arguments)))
+        else:
+            subset = range(len(head.arguments), self.settings.max_vars)
         for xs in permutations(subset, len(body_vars)):
             xs = head.arguments + xs
             new_body = []

popper/gen3.py

@@ -552,6 +552,10 @@ def find_variants3(self, rule, ruleid=0):
         head, body = rule
         head_arity = len(self.settings.head_literal.arguments)
         body_vars = frozenset(x for literal in body for x in literal.arguments if x >= head_arity)
+        if max_rule_vars:
+            subset = range(len(head.arguments), len(body_vars | set(head.arguments)))
+        else:
+            subset = range(len(head.arguments), self.settings.max_vars)
         subset = range(head_arity, self.settings.max_vars)
         for xs in permutations(subset, len(body_vars)):
             xs = head.arguments + xs