def test_optional(self):
tree = rule_grammar.parse('boy = "howdy"?\n')
rules, default_rule = RuleVisitor().visit(tree)
howdy = 'howdy'
# It should turn into a Node from the Optional and another from the
# Literal within.
self.assertEqual(default_rule.parse(howdy), Node(default_rule, howdy, 0, 5, children=[
Node(Literal("howdy"), howdy, 0, 5)]))
def test_optional(self):
tree = rule_grammar.parse('boy = "howdy"?\n')
_, default_rule = RuleVisitor().visit(tree)
howdy = 'howdy'
# It should turn into a Node from the Optional and another from the
# Literal within.
eq_(
default_rule.parse(howdy),
Node('boy',
howdy,
0,
5,
children=[Node('__Literal__', howdy, 0, 5)]))
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 = rule_grammar.parse('''number = ~"[0-9]+"\n''')
_, default_rule = RuleVisitor().visit(tree)
text = '98'
eq_(default_rule.parse(text), Node('number', text, 0, 2))
def test_undefined_rule(self):
"""Make sure we throw the right exception on undefined rules."""
tree = rule_grammar.parse('boy = howdy\n')
assert_raises(UndefinedLabel, RuleVisitor().visit, tree)