def _parse_string(source: Source, string_regex=BASIC_STRING, separator='"') -> str:
source.expect(separator)
res = []
while True:
if not source.consume_regex(string_regex):
raise DoesNotMatch('Invalid string starting from {text}'
.format(text=source._text[:100]))
res.append(source.last_consumed)
# start of some escape character
if not source.consume('\\'):
break
# do nothing if new line chars encountered
# corresponds to \
if source.consume_regex(NEWLINE_ESCAPE_CHARS_REGEX):
pass
# read unicode characters
elif source.consume_regex(SHORT_UNICODE_REGEX) or source.consume_regex(LONG_UNICODE_REGEX):
res.append(chr(int(source.last_consumed, 16)))
else:
# fail if no escape character follows
source.expect_regex(ESCAPE_CHARS_REGEX)
res.append(ESCAPES_MAPPING[source.last_consumed])
source.expect(separator)
return ''.join(res)
def parse_line_comment(source: Source) -> Comment:
source.expect('#')
source.consume_regex(COMMENT_REGEX)
text = source.last_consumed
source.expect_regex(re.compile(r'(?P<res>\n|\Z)'))
return Comment(text)
def test_expect_string_regex_true(self):
text = '"Hello"'
s = Source(text)
s.expect_regex(BASIC_STRING)