def _define_parser(self, locale, grammar):
"""
Build a parser for ``grammar`` and return it.
:param locale: The locale of the ``grammar``.
:type locale: basestring
:param grammar: The grammar for the parser to be built.
:type grammar: Grammar
:return: The convertible parser built from ``grammar``.
:rtype: ConvertibleParser
Here the ``locale`` is not used.
"""
parser = ConvertibleParser(grammar)
return parser
def __init__(self, *args, **kwargs):
super(BaseGrammarTest, self).__init__(*args, **kwargs)
# Let's use the convertible parser to ease testing:
self.parser = ConvertibleParser(self.grammar)
def test_custom_tokens_against_trees(self):
"""
All the custom tokens in the grammar must be taken into account by the
parser.
To test that custom tokens are used, and in order to test many scenarios
writen few lines of code, we're going to convert operation nodes into
boolean expressions (using the relevant grammar), and then these
expressions will be parsed to check if the result is the original
tree.
"""
grammars = (
# A grammar that overrides all the default tokens:
Grammar(
**{
'not': "not",
'and': "and",
'xor': "xor",
'or': "or",
'eq': "equals",
'ne': "different-from",
'lt': "less-than",
'le': "less-equal",
'gt': "greater-than",
'ge': "greater-equal",
'belongs_to': "belongs-to",
'is_subset': "is-subset-of",
'set_start': "\\",
'set_end': "/",
'element_separator': ";",
'arguments_start': "[",
'arguments_end': "]",
'arguments_separator': ";",
'namespace_separator': ".",
}),
# Now let's try a grammar where some operators represent the
# initial characters of other operators:
Grammar(
**{
'eq': "is",
'ne': "isn't",
'lt': "is less than",
'gt': "is greater than",
'le': "is less than or equal to",
'ge': "is greater than or equal to",
'belongs_to': "is included in",
'is_subset': "is subset of",
}))
for grammar_num in range(len(grammars)):
grammar = grammars[grammar_num]
parser = ConvertibleParser(grammar)
convert_to_string = StringConverter(grammar)
for operation in self.expressions.values():
expression = convert_to_string(operation)
# Using a Nose test generator:
def check():
new_operation = parser(expression).root_node
eq_(
operation, new_operation,
u'Original operation: %s --- Returned operation: %s' %
(repr(operation), repr(new_operation)))
check.description = (u"The following expression is valid in "
u"the grammar #%r: %r" %
(grammar_num, expression))
yield check
