def test_alternation():
(nfa1, q01, f1) = nfa_to_triple(make_nfa1())
(nfa2, q02, f2) = nfa_to_triple(make_nfa2())
(nfa, q0, f) = alternation(nfa1, q01, f1, nfa2, q02, f2)
assert accepts("xaab", nfa) == False
assert accepts("x", nfa) == True
assert accepts("aab", nfa) == True
def test_one_or_more():
(nfa, q0, f) = nfa_to_triple(make_nfa1())
(nfa, q0, f) = one_or_more(nfa, q0, f)
assert accepts("", nfa) == False
assert accepts("x", nfa) == True
assert accepts("xx", nfa) == True
assert accepts("a", nfa) == False
def test_thompson_compile_nfa_alternation():
(nfa, q0, f) = thompson_compile_nfa("a*|b")
if in_ipynb():
ipynb_display_graph(nfa)
assert not accepts("bbbbb", nfa)
assert accepts("b", nfa)
assert accepts("aaaaaa", nfa)
def test_thompson_compile_nfa_one_or_more():
(nfa, q0, f) = thompson_compile_nfa("(ab+)+")
if in_ipynb():
ipynb_display_graph(nfa)
assert not accepts("", nfa)
assert not accepts("b", nfa)
assert accepts("abbbbb", nfa)
assert accepts("abbbbbabbbbbabbbbb", nfa)
def test_parse_bracket_custom():
s = "[X-Z03a-e]"
chars = parse_bracket(s)
(nfa, q0, f) = bracket(chars)
for a in "XYZ03abcde":
assert accepts(a, nfa) is True
for a in "ABC12456789fghi":
assert accepts(a, nfa) is False
def test_thompson_compile_nfa_concatenation():
(nfa, q0, f) = thompson_compile_nfa("a+b+")
if in_ipynb():
ipynb_display_graph(nfa)
assert not accepts("abab", nfa)
assert not accepts("aaa", nfa)
assert not accepts("bbb", nfa)
assert accepts("ab", nfa)
assert accepts("aaaaaabbbbbb", nfa)
def test_thompson_compile_nfa_bracket_repetitions():
(nfa, q0, f) = thompson_compile_nfa("[x-z]{1,3}")
if in_ipynb():
ipynb_display_graph(nfa)
for w in ["x", "y", "xx", "xy", "zy", "xxx", "yyy", "zzz", "xyz", "zyx"]:
assert accepts(w, nfa) is True
for w in ["", "xxxx", "aaa"]:
assert accepts(w, nfa) is False
(nfa, q0, f) = thompson_compile_nfa("x{3}")
assert accepts("xxx", nfa)
def test_thompson_compile_nfa_repetition():
(nfa, q0, f) = thompson_compile_nfa("((ab){3})*")
if in_ipynb():
ipynb_display_graph(nfa)
for i in range(7):
assert accepts("ab" * i,
nfa) == (i % 3 == 0), f"w = {'ab' * i}, i = {i}"
def test_repetition():
(nfa, q0, f) = nfa_to_triple(make_nfa1())
m = 4
(nfa, q0, f) = repetition(nfa, q0, f, m)
words = ["x" * i for i in range(10)]
# Exactly m repetition
for (i, w) in enumerate(words):
assert accepts(w, nfa) == (i == m)
def test_repetition_range():
a = "a"
for (m, n) in [(3, 5), (0, 3), (3, 3), (3, None)]:
(nfa, q0, f) = literal(a)
(nfa, q0, f) = repetition_range(nfa, q0, f, m, n)
for i in range(10):
expected = (m <= i) and (n is None or i <= n)
w = a * i
obtained = accepts(w, nfa)
assert obtained == expected, f"(m, n) = {(m, n)} i = {i} w = {w}"
def test_escaped_operator():
(nfa, q0, f) = thompson_compile_nfa("a\\?b")
assert accepts("a?b", nfa) == True
assert accepts("ab", nfa) == False
assert accepts("b", nfa) == False
(nfa, q0, f) = thompson_compile_nfa("a?b")
assert accepts("a?b", nfa) == False
assert accepts("ab", nfa) == True
assert accepts("b", nfa) == True
for regexp in r"\|", r"\.", r"\*", r"\+", r"\(", r"\)", r"\{", r"\}", r"\[", r"\]":
(nfa, q0, f) = thompson_compile_nfa(regexp)
assert accepts(regexp.replace("\\", ""), nfa)
regexp = r"\|\.\*\+\(\)\{\}\[\]"
(nfa, q0, f) = thompson_compile_nfa(regexp)
accepts(regexp.replace("\\", ""), nfa)
def test_escaped_classes():
whole_alphabet = DEFAULT_ALPHABET
escaped_classes = [r"\d", r"\w", r"\s", r"\D", r"\W", r"\S"]
map_escape_allowed = {
r: set(parse_escaped(r, whole_alphabet))
for r in escaped_classes
}
for regexp in [r"\d", r"\w", r"\s", r"\D", r"\W", r"\S"]:
allowed = map_escape_allowed[regexp.lower()]
if regexp.lower() != regexp:
allowed = set(whole_alphabet) - allowed
(nfa, q0, f) = thompson_compile_nfa(regexp, whole_alphabet)
for a in whole_alphabet:
assert accepts(a, nfa) == (a in allowed), \
f"regexp = {regexp} a = '{a}' ({ord(a)}) allowed = '{allowed}' obtained = {accepts(a, nfa)} expected = {a in allowed}"
def test_thompson_compile_nfa_zero_or_one():
(nfa, q0, f) = thompson_compile_nfa("(ab?)*")
if in_ipynb():
ipynb_display_graph(nfa)
assert accepts("", nfa)
assert not accepts("b", nfa)
assert accepts("a", nfa)
assert accepts("ab", nfa)
assert accepts("aba", nfa)
assert not accepts("abb", nfa)
def test_thompson_compile_nfa_escaped_operators():
regexp = r"\|\.\*\+\(\)\{\}\[\]aa"
(nfa, q0, f) = thompson_compile_nfa(regexp)
accepts(regexp.replace("\\", ""), nfa)
if in_ipynb():
ipynb_display_graph(nfa)
def test_thompson_compile_nfa():
(nfa, q0, f) = thompson_compile_nfa("(a?b)*?c+d")
if in_ipynb():
ipynb_display_graph(nfa)
assert accepts("babbbababcccccd", nfa)