def test_round_trip(self):
"""Test a simple round trip.
Parse a simple grammar, turn the parse tree into a map of expressions,
and use that to parse another piece of text.
Not everything was implemented yet, but it was a big milestone and a
proof of concept.
"""
tree = peg_grammar.parse("""number = ~"[0-9]+"\n""")
rules, default_rule = PegVisitor().visit(tree)
text = "98"
eq_(default_rule.parse(text), Node("number", text, 0, 2))
def test_successes(self):
"""Make sure the PEG recognition grammar succeeds on various inputs."""
assert peg_grammar["label"].parse("_")
assert peg_grammar["label"].parse("jeff")
assert peg_grammar["label"].parse("_THIS_THING")
assert peg_grammar["atom"].parse("some_label")
assert peg_grammar["atom"].parse('"some literal"')
assert peg_grammar["atom"].parse('~"some regex"i')
assert peg_grammar["quantified"].parse('~"some regex"i*')
assert peg_grammar["quantified"].parse("thing+")
assert peg_grammar["quantified"].parse('"hi"?')
assert peg_grammar["term"].parse("this")
assert peg_grammar["term"].parse("that+")
assert peg_grammar["sequence"].parse("this that? other")
assert peg_grammar["ored"].parse('this / that+ / "other"')
assert peg_grammar["anded"].parse('this & that+ & "other"')
assert peg_grammar["poly_term"].parse('this & that+ & "other"')
assert peg_grammar["poly_term"].parse('this / that? / "other"+')
assert peg_grammar["poly_term"].parse("this? that other*")
assert peg_grammar["rhs"].parse("this")
assert peg_grammar["rhs"].parse("this? that other*")
assert peg_grammar["rule"].parse("this = that\r")
assert peg_grammar["rule"].parse("this = the? that other* \t\r")
assert peg_grammar["rule"].parse('the=~"hi*"\n')
assert peg_grammar.parse(
"""
this = the? that other*
that = "thing"
the=~"hi*"
other = "ahoy hoy"
"""
)
def test_undefined_rule(self):
"""Make sure we throw the right exception on undefined rules."""
tree = peg_grammar.parse("boy = howdy\n")
assert_raises(UndefinedLabel, PegVisitor().visit, tree)
