def __parse_property_expression(stream, PropertyLetter, EqualConditionPossibleF=True):
"""Parses an expression of the form '\? { X [ = Y] }' where
? = PropertyLetter. If the '=' operator is present then
two fields are returned first = left hand side, second =
right hand side. Othewise an element is returned.
"""
assert len(PropertyLetter) == 1
assert type(PropertyLetter) == str
assert type(EqualConditionPossibleF) == bool
# verify '\?'
x = stream.read(2)
if x != "\\" + PropertyLetter:
raise RegularExpressionException("Unicode property letter '\\%s' expected, received '%s'." % x)
skip_whitespace(stream)
x = stream.read(1)
if x != "{":
raise RegularExpressionException("Unicode property '\\%s' not followed by '{'." % PropertyLetter)
content = __snap_until(stream, "}")
fields = content.split("=")
if len(fields) == 0:
raise RegularExpressionException("Unicode property expression '\\%s{}' cannot have no content.")
if len(fields) > 2:
raise RegularExpressionException("Unicode property expression '\\%s' can have at maximum one '='.")
if not EqualConditionPossibleF and len(fields) == 2:
raise RegularExpressionException("Unicode property expression '\\%s' does not allow '=' conditions")
return map(lambda x: x.strip(), fields)
def __snap_repetition_range(the_state_machine, stream):
"""Snaps a string that represents a repetition range. The following
syntaxes are supported:
'?' one or none repetition
'+' one or arbitrary repetition
'*' arbitrary repetition (even zero)
'{n}' exactly 'n' repetitions
'{m,n}' from 'm' to 'n' repetitions
'{n,}' arbitrary, but at least 'n' repetitions
"""
assert the_state_machine.__class__.__name__ == "StateMachine", \
"received object of type '%s'" % the_state_machine.__class__.__name__ + "\n" + \
repr(the_state_machine)
position_0 = stream.tell()
x = stream.read(1)
if x == "+": result = repeat.do(the_state_machine, 1)
elif x == "*": result = repeat.do(the_state_machine)
elif x == "?": result = repeat.do(the_state_machine, 0, 1)
elif x == "{":
repetition_range_str = __snap_until(stream, "}")
if len(repetition_range_str) and not repetition_range_str[0].isdigit():
# no repetition range, so everything remains as it is
stream.seek(position_0)
return the_state_machine
try:
if repetition_range_str.find(",") == -1:
# no ',' thus "match exactly a certain number":
# e.g. {4} = match exactly four repetitions
number = int(repetition_range_str)
result = repeat.do(the_state_machine, number, number)
return result
# a range of numbers is given
fields = repetition_range_str.split(",")
fields = map(lambda x: x.strip(), fields)
number_1 = int(fields[0].strip())
if fields[1] == "": number_2 = -1 # e.g. {2,}
else: number_2 = int(fields[1].strip()) # e.g. {2,5}
# produce repeated state machine
result = repeat.do(the_state_machine, number_1, number_2)
return result
except:
raise RegularExpressionException("error while parsing repetition range expression '%s'" \
% repetition_range_str)
else:
# no repetition range, so everything remains as it is
stream.seek(position_0)
return the_state_machine
return result
def __snap_repetition_range(the_state_machine, stream):
"""Snaps a string that represents a repetition range. The following
syntaxes are supported:
'?' one or none repetition
'+' one or arbitrary repetition
'*' arbitrary repetition (even zero)
'{n}' exactly 'n' repetitions
'{m,n}' from 'm' to 'n' repetitions
'{n,}' arbitrary, but at least 'n' repetitions
"""
assert the_state_machine.__class__.__name__ == "StateMachine", \
"received object of type '%s'" % the_state_machine.__class__.__name__ + "\n" + \
repr(the_state_machine)
position_0 = stream.tell()
x = stream.read(1)
if x == "+": result = repeat.do(the_state_machine, 1)
elif x == "*": result = repeat.do(the_state_machine)
elif x == "?": result = repeat.do(the_state_machine, 0, 1)
elif x == "{":
repetition_range_str = __snap_until(stream, "}")
if len(repetition_range_str) and not repetition_range_str[0].isdigit():
# no repetition range, so everything remains as it is
stream.seek(position_0)
return the_state_machine
try:
if repetition_range_str.find(",") == -1:
# no ',' thus "match exactly a certain number":
# e.g. {4} = match exactly four repetitions
number = int(repetition_range_str)
result = repeat.do(the_state_machine, number, number)
return result
# a range of numbers is given
fields = repetition_range_str.split(",")
fields = map(lambda x: x.strip(), fields)
number_1 = int(fields[0].strip())
if fields[1] == "": number_2 = -1 # e.g. {2,}
else: number_2 = int(fields[1].strip()) # e.g. {2,5}
# produce repeated state machine
result = repeat.do(the_state_machine, number_1, number_2)
return result
except:
raise RegularExpressionException("error while parsing repetition range expression '%s'" \
% repetition_range_str)
else:
# no repetition range, so everything remains as it is
stream.seek(position_0)
return the_state_machine
return result
def snap_property_set(stream):
position = stream.tell()
x = stream.read(2)
if x == "\\P":
stream.seek(position)
return property.do(stream)
elif x == "\\N":
stream.seek(position)
return property.do_shortcut(stream, "N", "na") # UCS Property: Name
elif x == "\\G":
stream.seek(position)
return property.do_shortcut(stream, "G", "gc") # UCS Property: General_Category
elif x == "\\E":
skip_whitespace(stream)
if check(stream, "{") == False:
error_msg("Missing '{' after '\\E'.", stream)
encoding_name = __snap_until(stream, "}").strip()
return codec_db.get_supported_unicode_character_set(encoding_name, stream)
else:
stream.seek(position)
return None
def snap_property_set(stream):
position = stream.tell()
x = stream.read(2)
if x == "\\P":
stream.seek(position)
return property.do(stream)
elif x == "\\N":
stream.seek(position)
return property.do_shortcut(stream, "N", "na") # UCS Property: Name
elif x == "\\G":
stream.seek(position)
return property.do_shortcut(stream, "G",
"gc") # UCS Property: General_Category
elif x == "\\E":
skip_whitespace(stream)
if check(stream, "{") == False:
error_msg("Missing '{' after '\\E'.", stream)
encoding_name = __snap_until(stream, "}").strip()
return codec_db.get_supported_unicode_character_set(
encoding_name, stream)
else:
stream.seek(position)
return None
