def parse_named_character_class(self):
"""
Parse a named character class ([:...:]) subexpresion from the string at its current index.
@return: a CoverageSet object covering all the characters covered by the named class
"""
classes = {
u"alnum": [Parser.lowercase, Parser.uppercase, Parser.digits],
u"word": [Parser.lowercase, Parser.uppercase, Parser.digits, Parser.underscore],
u"alpha": [Parser.uppercase, Parser.lowercase],
u"blank": [Parser.space, Parser.tab],
u"cntrl": [(0, 31)],
u"digit": [Parser.digits],
u"graph": [(33, 127)],
u"lower": [Parser.lowercase],
u"print": [(32, 127)],
u"punct": [(ord(i), ord(i)) for i in "][!\"#$%&'()*+,./:;<=>?@\\^_`{|}~-"],
u"space": [(ord(i), ord(i)) for i in string.whitespace],
u"xdigit": [Parser.digits, (ord('a'), ord('f')), (ord('A'), ord('F'))],
u"upper": [Parser.uppercase]
}
unicode_classes = {
u"alnum": {False: [('alpha', None), ('digit', None)], True: []},
u"word": {False: [('alpha', None), ('gc', 'Mark'), ('digit', None), ('gc', 'Connector_Punctuation'), ('Join_Control', None)], True: []},
u"alpha": {False: [('alpha', None)], True: []},
u"blank": {False: [('gc', 'Space_Separator'), ('na1', 'CHARACTER TABULATION')], True: []},
u"cntrl": {False: [('gc', 'Control')], True: []},
u"digit": {False: [('gc', 'Decimal_Number')], True: []},
u"graph": {False: [], True: [('space', None), ('gc', 'Control'), ('gc', 'Surrogate'), ('gc', 'Unassigned')]},
u"lower": {False: [('Lowercase', None)], True: []},
u"print": {False: [('gc', 'Space_Separator'), ('na1', 'CHARACTER TABULATION')], True: [('space', None), ('gc', 'Control'), ('gc', 'Surrogate'), ('gc', 'Unassigned')]},
u"punct": {False: [('gc', 'Punctuation')], True: []},
u"space": {False: [('Whitespace', None)], True: []},
u"xdigit": {False: [('gc', 'Decimal_Number'), ('Hex_Digit', None)], True: []},
u"upper": {False: [('Uppercase', None)], True: []}
}
self.expect(u':')
class_name = ""
while self.next_is(string.ascii_letters):
class_name += self.get_next()
self.expect(":")
self.expect("]")
if self.is_unicode_defaults and class_name in unicode_classes:
class_queries = unicode_classes[class_name]
instance = UnicodeQuery.instance(self.unicode_db)
coverage = CoverageSet()
for k, v in class_queries[False]:
coverage.update(instance.query(k, v))
if len(class_queries[True]) > 0:
inverted_coverage = CoverageSet([(1, 0x10ffff)])
for k, v in class_queries[True]:
inverted_coverage.difference_update(instance.query(k, v))
coverage.update(inverted_coverage)
return coverage
elif not self.is_unicode_defaults and class_name in classes:
return CoverageSet(classes[class_name])
else:
raise RegexParserExceptionInternal("Character class '%s' not recognized" % class_name)
def parse_unicode_subexpression(self):
"""
Parse a single "NAME=VALUE" term for a unicode property.
@returns: A CoverageSet object containing the values covered by the term
"""
name = self.parse_unicode_word()
if self.get_next_if(u':='):
value = self.parse_unicode_word()
else:
value = None
coverage = UnicodeQuery.instance(self.unicode_db).query(name, value)
return coverage
def parse_unicode_name(self):
"""
Parse a unicode "{...}" expresion for querying unicode names.
@returns: A CoverageSet object containing all characters covered by
the specified unicode query
"""
self.expect("{")
name = self.parse_unicode_word()
coverage = UnicodeQuery.instance(self.unicode_db).query('na', name)
if coverage.empty():
raise ValueError("Name '{name}' not found".format(name=name))
return coverage
def parse_unicode_subexpression(self):
"""
Parse a single "NAME=VALUE" term for a unicode property.
@returns: A CoverageSet object containing the values covered by the term
"""
name = self.parse_unicode_word()
if self.get_next_if(u':='):
value = self.parse_unicode_word()
else:
value = None
coverage = UnicodeQuery.instance(self.unicode_db).query(name, value)
return coverage
def parse_unicode_name(self):
"""
Parse a unicode "{...}" expresion for querying unicode names.
@returns: A CoverageSet object containing all characters covered by
the specified unicode query
"""
self.expect("{")
name = self.parse_unicode_word()
coverage = UnicodeQuery.instance(self.unicode_db).query('na', name)
if coverage.empty():
raise ValueError("Name '{name}' not found".format(name=name))
return coverage
def parse_named_character_class(self):
"""
Parse a named character class ([:...:]) subexpresion from the string at its current index.
@return: a CoverageSet object covering all the characters covered by the named class
"""
classes = {
u"alnum": [Parser.lowercase, Parser.uppercase, Parser.digits],
u"word": [
Parser.lowercase, Parser.uppercase, Parser.digits,
Parser.underscore
],
u"alpha": [Parser.uppercase, Parser.lowercase],
u"blank": [Parser.space, Parser.tab],
u"cntrl": [(0, 31)],
u"digit": [Parser.digits],
u"graph": [(33, 127)],
u"lower": [Parser.lowercase],
u"print": [(32, 127)],
u"punct":
[(ord(i), ord(i)) for i in "][!\"#$%&'()*+,./:;<=>?@\\^_`{|}~-"],
u"space": [(ord(i), ord(i)) for i in string.whitespace],
u"xdigit":
[Parser.digits, (ord('a'), ord('f')), (ord('A'), ord('F'))],
u"upper": [Parser.uppercase]
}
unicode_classes = {
u"alnum": {
False: [('alpha', None), ('digit', None)],
True: []
},
u"word": {
False: [('alpha', None), ('gc', 'Mark'), ('digit', None),
('gc', 'Connector_Punctuation'),
('Join_Control', None)],
True: []
},
u"alpha": {
False: [('alpha', None)],
True: []
},
u"blank": {
False: [('gc', 'Space_Separator'),
('na1', 'CHARACTER TABULATION')],
True: []
},
u"cntrl": {
False: [('gc', 'Control')],
True: []
},
u"digit": {
False: [('gc', 'Decimal_Number')],
True: []
},
u"graph": {
False: [],
True: [('space', None), ('gc', 'Control'), ('gc', 'Surrogate'),
('gc', 'Unassigned')]
},
u"lower": {
False: [('Lowercase', None)],
True: []
},
u"print": {
False: [('gc', 'Space_Separator'),
('na1', 'CHARACTER TABULATION')],
True: [('space', None), ('gc', 'Control'), ('gc', 'Surrogate'),
('gc', 'Unassigned')]
},
u"punct": {
False: [('gc', 'Punctuation')],
True: []
},
u"space": {
False: [('Whitespace', None)],
True: []
},
u"xdigit": {
False: [('gc', 'Decimal_Number'), ('Hex_Digit', None)],
True: []
},
u"upper": {
False: [('Uppercase', None)],
True: []
}
}
self.expect(u':')
class_name = ""
while self.next_is(string.ascii_letters):
class_name += self.get_next()
self.expect(":")
self.expect("]")
if self.is_unicode_defaults and class_name in unicode_classes:
class_queries = unicode_classes[class_name]
instance = UnicodeQuery.instance(self.unicode_db)
coverage = CoverageSet()
for k, v in class_queries[False]:
coverage.update(instance.query(k, v))
if len(class_queries[True]) > 0:
inverted_coverage = CoverageSet([(1, 0x10ffff)])
for k, v in class_queries[True]:
inverted_coverage.difference_update(instance.query(k, v))
coverage.update(inverted_coverage)
return coverage
elif not self.is_unicode_defaults and class_name in classes:
return CoverageSet(classes[class_name])
else:
raise RegexParserExceptionInternal(
"Character class '%s' not recognized" % class_name)
class Parser(object):
"""
Converts a string containing a regular expression into a visitable regular expression object.
"""
lowercase = (ord('a'), ord('z'))
uppercase = (ord('A'), ord('Z'))
digits = (ord('0'), ord('9'))
underscore = (ord('_'), ord('_'))
tab = (9, 9)
line_feed = (10, 10)
vertical_tab = (11, 11)
form_feed = (12, 12)
carriage_return = (13, 13)
space = ((ord(' '), ord(' ')))
special = u'(){}[].^$*+-~&?|:'
closing = u')}]'
unicode_db = UnicodeQuery.find_db()
set_operators = "-&~|"
def __init__(self,
text,
is_case_insensitive=False,
is_unicode_defaults=False,
is_literal=False,
unicode_db=None):
"""
@param text: string containing the regular expression
@param is_case_insensitive: boolean which is true if the regular expression should be case insensitive
@param unicode_db: location of the folder containing the JSON unicode property data files
"""
self.text = text
self.index = 0
self.is_case_insensitive = is_case_insensitive
self.is_unicode_defaults = is_unicode_defaults
self.is_literal = is_literal
if unicode_db is not None:
self.unicode_db = unicode_db
elif Parser.unicode_db is None and unicode_db is None:
raise ValueError(
"Unicode database not found and no database provided")
def parse(self):
"""
Parse the string from its current index and return a regular expression
@return: a visitable regular expression object from the Regex package
"""
regex_object = self.parse_alternation()
if self.index < len(self.text):
self.expect(u'end of pattern')
return regex_object
def parse_alternation(self):
"""
Parse the string from its current index into an alternation or an expression that can be contained by an alternation.
@return: a visitable regular expression object from the Regex package.
"""
concatenations = [self.parse_concatenation()]
while self.get_next_if(u'|'):
concatenations.append(self.parse_concatenation())
if len(concatenations) > 1:
return Regex.Alternation(concatenations)
else:
return concatenations[0]
def parse_concatenation(self):
"""
Parse the string from its current index into a concatenation or an expression that can be contained by an concatenation.
@return: a visitable regular expression object from the Regex package.
"""
repetitions = [self.parse_qualified()]
while self.next_is_not(u'|)'):
repetitions.append(self.parse_qualified())
if len(repetitions) > 1:
return Regex.Concatenation(repetitions)
else:
return repetitions[0]
def parse_qualified(self):
"""
Parse the string from its current index into a repetition or an expression that can be contained by an repetition.
@return: a visitable regular expression object from the Regex package.
"""
child = self.parse_character()
if self.get_next_if(u'*'):
return Regex.Repetition(child, 0, Regex.Repetition.Infinity)
elif self.get_next_if(u'+'):
return Regex.Repetition(child, 1, Regex.Repetition.Infinity)
elif self.get_next_if(u'?'):
return Regex.Repetition(child, 0, 1)
# Need to look ahead two characters because it might be a variable following this one
elif self.next_is(u'{') and self.nth_next_is_not(
2, string.ascii_letters + '.'):
self.get_next()
return self.parse_repetition(child)
else:
return child
def parse_character(self):
"""
Parse the string from its current index ino a character set or a sub-expression
@return: a visitable regular expression object from the Regex package.
"""
if self.get_next_if(u'['):
return self.parse_character_class()
elif self.get_next_if(u'('):
child = self.parse_alternation()
self.expect(u')')
return child
elif self.get_next_if(u'{'):
return self.parse_variable()
else:
return self.parse_literal()
def parse_literal(self, suppress_case_insensitive=False):
"""
Parse a single character from the string, from its current index into a literal expression
@return: a Regex.Literal or Regex.LiteralExcept object representing the character.
"""
def get_literal(character, is_case_insensitive):
if is_case_insensitive and not suppress_case_insensitive:
lowercase = character.lower()
uppercase = character.upper()
if lowercase != uppercase:
return Regex.Literal([(ord(lowercase), ord(lowercase)),
(ord(uppercase), ord(uppercase))])
return Regex.Literal([(ord(character), ord(character))])
if self.get_next_if(u'.'):
return Regex.Literal([(1, 0x10FFFF)])
elif self.get_next_if(u'\\'):
if self.get_next_if(u'w'):
return Regex.Literal(
[Parser.lowercase, Parser.uppercase, Parser.underscore])
elif self.get_next_if(u'W'):
return Regex.LiteralExcept(
[Parser.lowercase, Parser.uppercase, Parser.underscore])
elif self.get_next_if(u'r'):
return Regex.Literal([Parser.carriage_return])
elif self.get_next_if(u'n'):
return Regex.Literal([Parser.line_feed])
elif self.get_next_if(u't'):
return Regex.Literal([Parser.tab])
elif self.get_next_if(u's'):
return Regex.Literal([Parser.space])
elif self.get_next_if(u'd'):
return Regex.Literal([Parser.digits])
elif self.get_next_if(u'v'):
return Regex.Literal([Parser.vertical_tab])
elif self.get_next_if(u'f'):
return Regex.Literal([Parser.form_feed])
elif self.get_next_if(u'x'):
codepoint = self.parse_hex_digits(2)
return Regex.Literal([(codepoint, codepoint)])
elif self.get_next_if(u'p'):
coverage = self.parse_unicode_expression()
return Regex.Literal(coverage)
elif self.get_next_if(u'N'):
coverage = self.parse_unicode_name()
return Regex.Literal(coverage)
elif self.get_next_if(u'P'):
coverage = self.parse_unicode_expression()
return Regex.LiteralExcept(coverage)
elif self.get_next_if(u'u'):
codepoint = self.parse_hex_digits(4)
return Regex.Literal([(codepoint, codepoint)])
elif self.get_next_if(u'U'):
codepoint = self.parse_hex_digits(6)
return Regex.Literal([(codepoint, codepoint)])
else:
return get_literal(self.get_next(), self.is_case_insensitive)
else:
character = self.get_next()
if character in Parser.closing:
raise RegexParserExpected("character", self.text,
self.index - 1)
elif character in Parser.special:
raise RegexParserInvalidCharacter(character)
return get_literal(character, self.is_case_insensitive)
def parse_hex_digits(self, num_digits):
hex_text = ''
for i in range(num_digits):
if not self.next_is(string.hexdigits):
self.expect(string.hexdigits, name='hexadecimal digit')
hex_text += self.get_next()
value = int(hex_text, 16)
if (value > 0x10ffff):
raise RegexParserUnicodeCodepointOutOfRange(value)
return value
def parse_variable(self):
"""
Parse a variable instance from the string at its current index
@return: a Regex.Variable object representing the variable instance
"""
variable_name = ''
while self.next_is(string.ascii_letters + '.'):
variable_name += self.get_next()
self.expect("}")
return Regex.Variable(variable_name)
def parse_repetition(self, child):
"""
Parse a {min, max} expression from the string at its current index
@param child: a visital object from the Regex package containing the repeated expression.
@return: a Regex.Repetition object representing the repetition.
"""
first = self.parse_integer()
self.expect(u',')
last = self.parse_integer()
self.expect(u'}')
if first > last:
raise RegexParserExceptionInternal(
"Minimum repetition (%d) cannot be larger than maximum repetition (%d)."
% (first, last))
return Regex.Repetition(child, first, last)
def parse_integer(self):
"""
Parse an integer from the string at its current index.
@return: the integer parsed from the string.
"""
number = ''
if not self.next_is(string.digits):
self.expect(u'integer')
while self.next_is(string.digits):
number += self.get_next()
return int(number)
def expect(self, character, name=None):
"""
Raise an exception if the character at the current index of the string is not a specific value.
@param character: the value that the current character should be.
"""
if not self.next_is(character):
if name is None:
raise RegexParserExpected(unicode(character), self.text,
self.index)
else:
raise RegexParserExpected(name, self.text, self.index)
self.index += 1
def get_next(self):
"""
Returns the next character, advances the stream, and throws an exception if at the end of the pattern
@return: String containing the next character
"""
if self.index >= len(self.text):
self.expect('character')
self.index += 1
return unicode(self.text[self.index - 1])
def get_next_if(self, characters):
"""
Advances the sream if the next character is one of a set of characters
@param characters: A string containing the characters for which to check
@return: Boolean if the next character is one of characters
"""
if self.next_is(characters):
self.get_next()
return True
return False
def next_is(self, characters):
"""
Returns true if the next character is at the current index of the string is one of a set of characters. False if not.
@param characters: the value that the current character should be.
@return: True if the next characters is in the expected set, False otherwise or if at end of string
"""
return self.nth_next_is(1, characters)
def nth_next_is(self, n, characters):
"""
Looks ahead n characters and returns true if the next nth character of the string is one of a set of characters. False if not.
@param n: how many characters to look ahead. Must be greater than 0
@param characters: the value that the current character should be.
@return: True if the next characters is in the expected set, False otherwise or if at end of string
"""
return n > 0 and self.index + n - 1 < len(
self.text) and self.text[self.index + n - 1] in characters
def next_is_not(self, characters):
"""
Returns true if the next character is not end-of-string and is not one of a set of characters. False if not
@param characters: the value that the current character should not be.
@return: True if the next character is not in the expected set, Fase otherwise or if at end of string
"""
return self.index < len(
self.text) and self.text[self.index] not in characters
def nth_next_is_not(self, n, characters):
"""
Looks ahead n characters and returns true if the next nth character of the string is not one of a set of characters. False if not.
@param n: how many characters to look ahead. Must be greater than 0
@param characters: the value that the current character should be.
@return: True if the next characters is in the expected set, False otherwise or if at end of string
"""
return n > 0 and self.index + n - 1 < len(
self.text) and self.text[self.index + n - 1] not in characters
def next_is_set_operator(self):
return self.next_is(Parser.set_operators) and self.nth_next_is(
2, self.text[self.index])
def parse_character_class(self):
"""
Parse a character class ([...]) expression from the string at its current index.
@return: a Regex.Literal object representing the characters
"""
characters = self.parse_character_class_expression()
return Regex.Literal([i for i in characters])
def parse_named_character_class(self):
"""
Parse a named character class ([:...:]) subexpresion from the string at its current index.
@return: a CoverageSet object covering all the characters covered by the named class
"""
classes = {
u"alnum": [Parser.lowercase, Parser.uppercase, Parser.digits],
u"word": [
Parser.lowercase, Parser.uppercase, Parser.digits,
Parser.underscore
],
u"alpha": [Parser.uppercase, Parser.lowercase],
u"blank": [Parser.space, Parser.tab],
u"cntrl": [(0, 31)],
u"digit": [Parser.digits],
u"graph": [(33, 127)],
u"lower": [Parser.lowercase],
u"print": [(32, 127)],
u"punct":
[(ord(i), ord(i)) for i in "][!\"#$%&'()*+,./:;<=>?@\\^_`{|}~-"],
u"space": [(ord(i), ord(i)) for i in string.whitespace],
u"xdigit":
[Parser.digits, (ord('a'), ord('f')), (ord('A'), ord('F'))],
u"upper": [Parser.uppercase]
}
unicode_classes = {
u"alnum": {
False: [('alpha', None), ('digit', None)],
True: []
},
u"word": {
False: [('alpha', None), ('gc', 'Mark'), ('digit', None),
('gc', 'Connector_Punctuation'),
('Join_Control', None)],
True: []
},
u"alpha": {
False: [('alpha', None)],
True: []
},
u"blank": {
False: [('gc', 'Space_Separator'),
('na1', 'CHARACTER TABULATION')],
True: []
},
u"cntrl": {
False: [('gc', 'Control')],
True: []
},
u"digit": {
False: [('gc', 'Decimal_Number')],
True: []
},
u"graph": {
False: [],
True: [('space', None), ('gc', 'Control'), ('gc', 'Surrogate'),
('gc', 'Unassigned')]
},
u"lower": {
False: [('Lowercase', None)],
True: []
},
u"print": {
False: [('gc', 'Space_Separator'),
('na1', 'CHARACTER TABULATION')],
True: [('space', None), ('gc', 'Control'), ('gc', 'Surrogate'),
('gc', 'Unassigned')]
},
u"punct": {
False: [('gc', 'Punctuation')],
True: []
},
u"space": {
False: [('Whitespace', None)],
True: []
},
u"xdigit": {
False: [('gc', 'Decimal_Number'), ('Hex_Digit', None)],
True: []
},
u"upper": {
False: [('Uppercase', None)],
True: []
}
}
self.expect(u':')
class_name = ""
while self.next_is(string.ascii_letters):
class_name += self.get_next()
self.expect(":")
self.expect("]")
if self.is_unicode_defaults and class_name in unicode_classes:
class_queries = unicode_classes[class_name]
instance = UnicodeQuery.instance(self.unicode_db)
coverage = CoverageSet()
for k, v in class_queries[False]:
coverage.update(instance.query(k, v))
if len(class_queries[True]) > 0:
inverted_coverage = CoverageSet([(1, 0x10ffff)])
for k, v in class_queries[True]:
inverted_coverage.difference_update(instance.query(k, v))
coverage.update(inverted_coverage)
return coverage
elif not self.is_unicode_defaults and class_name in classes:
return CoverageSet(classes[class_name])
else:
raise RegexParserExceptionInternal(
"Character class '%s' not recognized" % class_name)
def parse_character_class_subexpression(self):
"""
Parse either a group "[...]", a named character class "[:...:]", or a range "...-..."
@returns: a CoverageSet object containing the characters in the sub-expression
"""
if self.next_is(':'):
return self.parse_named_character_class()
expression = self.parse_character_class_expression()
return expression
return self.parse_character_class_range()
def parse_character_class_character(self):
"""
Parse a lingle literal, but accomodate sub-expressions such as "[:...:]" or "[...]"
@return: a CoverageSet object containing the characters that were parsed
"""
if self.get_next_if(u'['):
return self.parse_character_class_subexpression()
else:
return self.parse_literal(True).characters
def parse_character_class_range(self):
"""
Parse a range (e.g. a-z) expression from the string at its current index
@return: a CoverageSet object containing all the characters in the range
"""
start_literal = self.parse_character_class_character()
if self.next_is('-') and not self.nth_next_is(2, '-'):
self.get_next()
end_literal = self.parse_character_class_character()
else:
return start_literal
# Range must be two single characters with the end having a larger value than the start
if len(start_literal) > 1 or len(end_literal) > 1:
raise RegexParserInvalidCharacterRange(start_literal, end_literal)
start_ordinal = next(iter(start_literal))[0]
end_ordinal = next(iter(end_literal))[0]
if start_ordinal > end_ordinal:
raise RegexParserInvalidCharacterRange(unichr(start_ordinal),
unichr(end_ordinal))
if self.is_case_insensitive:
lower_start = ord(unichr(start_ordinal).lower())
lower_end = ord(unichr(end_ordinal).lower())
upper_start = ord(unichr(start_ordinal).upper())
upper_end = ord(unichr(end_ordinal).upper())
return CoverageSet([(lower_start, lower_end),
(upper_start, upper_end)])
else:
return CoverageSet([(start_ordinal, end_ordinal)])
def parse_character_class_terms(self):
"""
Parse a series of terms within a character class ("a-zbc", etc).
@returns: the union of their coverage
"""
coverage = CoverageSet()
coverage.update(self.parse_character_class_range())
while self.next_is_not(']\r\n') and not self.next_is_set_operator():
coverage.update(self.parse_character_class_range())
return coverage
def parse_character_class_expression(self):
"""
Parses the text after the left bracket of a "[...]" expression
@returns: a CoverageSet object covering all the characters covered by the character class.
"""
inverse = self.get_next_if(u'^')
coverage = self.parse_character_class_terms()
while self.next_is_set_operator():
operator = self.get_next()
self.get_next()
if self.next_is(u'])}'):
raise RegexParserExpected("expression term", self.text,
self.index)
rhs = self.parse_character_class_terms()
if operator == u'|':
coverage.update(rhs)
elif operator == u'&':
coverage.intersection_update(rhs)
elif operator == u'-':
coverage.difference_update(rhs)
elif operator == u'~':
intersection = CoverageSet.intersection(coverage, rhs)
coverage.update(rhs)
coverage.difference_update(intersection)
self.expect("]")
if inverse:
inverted_coverage = CoverageSet()
inverted_coverage.add(1, 0x10FFFF)
inverted_coverage.difference_update(coverage)
return inverted_coverage
return coverage
def parse_unicode_expression(self):
"""
Parse a unicode "{...}" expression for querying unicode properties.
@returns: A CoverageSet object containing all characters covered by
the specified unicode query.
"""
self.expect("{")
coverage = self.parse_unicode_subexpression()
while self.get_next_if(u'|'):
coverage.update(self.parse_unicode_subexpression())
self.expect("}")
return coverage
def parse_unicode_name(self):
"""
Parse a unicode "{...}" expresion for querying unicode names.
@returns: A CoverageSet object containing all characters covered by
the specified unicode query
"""
self.expect("{")
name = self.parse_unicode_word()
coverage = UnicodeQuery.instance(self.unicode_db).query('na', name)
if coverage.empty():
raise ValueError("Name '{name}' not found".format(name=name))
return coverage
def parse_unicode_subexpression(self):
"""
Parse a single "NAME=VALUE" term for a unicode property.
@returns: A CoverageSet object containing the values covered by the term
"""
name = self.parse_unicode_word()
if self.get_next_if(u':='):
value = self.parse_unicode_word()
else:
value = None
coverage = UnicodeQuery.instance(self.unicode_db).query(name, value)
return coverage
def parse_unicode_word(self):
"""
Scan a string, while skipping over whitespace, hyphens, and underscores.
@return: the filtered name that was parsed out.
"""
variable_name = ''
while True:
if self.next_is(' \t-_'):
self.get_next()
elif self.next_is(string.ascii_letters):
variable_name += self.get_next()
else:
break
if variable_name == '':
raise RegexParserExpected("string", self.text, self.index)
return variable_name
