import os, sys
curr_dir = os.path.dirname(os.path.realpath(__file__))
gdl_path = os.path.abspath(os.path.join(curr_dir, os.pardir))
sys.path.append(gdl_path)
from gdl import Lexer, Parser, Database, DatalogError, ParseError
DEFINE = 'GDL> '
QUERY = 'GDL? '
prompt = DEFINE
database = Database()
for filename in sys.argv[1:]:
# read in any files from the command line
with open(filename, 'r') as file:
tokens = Lexer.run_lex(file=file)
for tree in Parser.run_parse(tokens):
# print(tree)
database.define(tree)
try:
# interactive loop
while 1:
raw_string = input(prompt).strip()
if raw_string == '?':
prompt = QUERY
continue
elif raw_string == '.':
prompt = DEFINE
continue
elif not raw_string:
def test_fact_variable_argument_error(self):
children = [make_mock_node('x'), make_mock_node('?y')]
arg = make_mock_node('predicate', children)
with self.assertRaises(DatalogError):
Database().define_fact('foo', 1, [arg])
def setUp(self):
self.db = Database()
# FACTS
self.db.define_fact('foo', 3,
[make_mock_node(x) for x in ('a', 'b', 'c')])
self.db.define_fact('foo', 3,
[make_mock_node(x) for x in ('x', 'y', 'z')])
self.db.define_fact('foo', 3,
[make_mock_node(x) for x in ('x', 'y', 'x')])
self.db.define_fact('foo', 3,
[make_mock_node(x) for x in ('a', 'a', 'a')])
self.db.define_fact('bar', 2, [
make_mock_node('1'),
make_mock_node('x', [make_mock_node(x) for x in ('2', '3')])
])
# RULES
# Datalog 2.5
# > path(X,Y) :- path(X,Z), link(Z,Y).
# > path(X,Y) :- link(X,Y).
# > link(3,4).
# > link(2,3).
# > link(1,2).
path = make_mock_node('path',
[make_mock_node(x) for x in ('?x', '?z')])
link = make_mock_node('link',
[make_mock_node(x) for x in ('?z', '?y')])
self.db.define_rule('path', 2,
[make_mock_node(x) for x in ('?x', '?y')],
[path, link])
link = make_mock_node('link',
[make_mock_node(x) for x in ('?x', '?y')])
self.db.define_rule('path', 2,
[make_mock_node(x) for x in ('?x', '?y')], [link])
self.db.define_fact('link', 2, [make_mock_node(x) for x in ('3', '4')])
self.db.define_fact('link', 2, [make_mock_node(x) for x in ('2', '3')])
self.db.define_fact('link', 2, [make_mock_node(x) for x in ('1', '2')])
# NEGATION
# > x(1). x(2). x(3). x(4).
# > not_path(X, Y) :- x(X), x(Y), not(path(X, Y)).
self.db.define_fact('x', 1, [make_mock_node('1')])
self.db.define_fact('x', 1, [make_mock_node('2')])
self.db.define_fact('x', 1, [make_mock_node('3')])
self.db.define_fact('x', 1, [make_mock_node('4')])
xx = make_mock_node('x', [make_mock_node('?x')])
xy = make_mock_node('x', [make_mock_node('?y')])
path = make_mock_node('path',
[make_mock_node(x) for x in ('?y', '?x')])
self.db.define_rule('rpath', 2,
[make_mock_node(x) for x in ('?x', '?y')],
[xx, xy, path])
not_path = make_mock_node('not', [
make_mock_node('path', [make_mock_node(x) for x in ('?x', '?y')])
])
self.db.define_rule('not-path', 2,
[make_mock_node(x) for x in ('?x', '?y')],
[xx, xy, not_path])
# CYCLICAL RECURSION
# Datalog 2.5
# > s(1).
# > s(2).
# > t(1).
# > p(X) :- q(X), s(X).
# > q(X) :- p(X), t(X).
# > q(X) :- t(X).
self.db.define_fact('s', 1, [make_mock_node('1')])
self.db.define_fact('s', 1, [make_mock_node('2')])
self.db.define_fact('t', 1, [make_mock_node('1')])
p, q, s, t = [
make_mock_node(x, [make_mock_node('?x')])
for x in ('p', 'q', 's', 't')
]
self.db.define_rule('p', 1, [make_mock_node('?x')], [q, s])
self.db.define_rule('q', 1, [make_mock_node('?x')], [p, t])
self.db.define_rule('q', 1, [make_mock_node('?x')], [t])
# DISTINCT
# (<= (diff ?x ?y) (x ?x) (x ?y) (distinct ?x ?y))
distinct = make_mock_node(
'distinct',
[make_mock_node('?x'), make_mock_node('?y')])
xx = make_mock_node('x', [make_mock_node('?x')])
xy = make_mock_node('x', [make_mock_node('?y')])
self.db.define_rule('diff', 2,
[make_mock_node(x) for x in ('?x', '?y')],
[xx, xy, distinct])
# OR
# (<= (valid? ?x ?y) (not-path ?x ?y) (or (distinct ?y 4) (distinct ?x 4)))
d1 = make_mock_node(
'distinct',
[make_mock_node('?y'), make_mock_node('4')])
d2 = make_mock_node(
'distinct',
[make_mock_node('?x'), make_mock_node('4')])
or_ = make_mock_node('or', [d1, d2])
not_path = make_mock_node('not-path',
[make_mock_node(x) for x in ('?x', '?y')])
self.db.define_rule('valid?', 2,
[make_mock_node(x) for x in ('?x', '?y')],
[not_path, or_])
# 0-ARITY RULES
cell = make_mock_node('cell',
[make_mock_node(x) for x in ['?m', '?n', 'b']])
self.db.define_rule('open', 0, [], [make_mock_node('true', [cell])])
self.db.define_rule('terminal', 0, [],
[make_mock_node('not', [make_mock_node('open')])])
def test_fact_list_error(self):
with self.assertRaises(TypeError):
Database().define_fact('foo', 2, (1, 2))
