diff options
| -rw-r--r-- | prolog/util.py | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/prolog/util.py b/prolog/util.py index 11a6f94..e69d4d5 100644 --- a/prolog/util.py +++ b/prolog/util.py @@ -224,6 +224,24 @@ def map_vars(a, b, tokens, variables): return [t if t.type != 'VARIABLE' else t.clone(val=mapping[t.val]) for t in b] +# Return a set of predicate names (e.g. conc/3) used in [program]. +def used_predicates(program): + predicates = set() + def walk(tree): + if isinstance(tree, Tree): + if tree.label() == 'term' and len(tree) >= 3 and \ + isinstance(tree[0], Tree) and tree[0].label() == 'functor': + if len(tree) == 3: + predicates.add('{}/0'.format(tree[0][0])) + else: + predicates.add('{}/{}'.format(tree[0][0], (len(tree[2])+1)//2)) + for subtree in tree: + walk(subtree) + tree = parse(program) + if tree is not None: + walk(tree) + return predicates + # Basic sanity check. if __name__ == '__main__': var_names = {} |