| """JSON token scanner | |
| """ | |
| import re | |
| try: | |
| from _json import make_scanner as c_make_scanner | |
| except ImportError: | |
| c_make_scanner = None | |
| __all__ = ['make_scanner'] | |
| NUMBER_RE = re.compile( | |
| r'(-?(?:0|[1-9]\d*))(\.\d+)?([eE][-+]?\d+)?', | |
| (re.VERBOSE | re.MULTILINE | re.DOTALL)) | |
| def py_make_scanner(context): | |
| parse_object = context.parse_object | |
| parse_array = context.parse_array | |
| parse_string = context.parse_string | |
| match_number = NUMBER_RE.match | |
| strict = context.strict | |
| parse_float = context.parse_float | |
| parse_int = context.parse_int | |
| parse_constant = context.parse_constant | |
| object_hook = context.object_hook | |
| object_pairs_hook = context.object_pairs_hook | |
| memo = context.memo | |
| def _scan_once(string, idx): | |
| try: | |
| nextchar = string[idx] | |
| except IndexError: | |
| raise StopIteration(idx) from None | |
| if nextchar == '"': | |
| return parse_string(string, idx + 1, strict) | |
| elif nextchar == '{': | |
| return parse_object((string, idx + 1), strict, | |
| _scan_once, object_hook, object_pairs_hook, memo) | |
| elif nextchar == '[': | |
| return parse_array((string, idx + 1), _scan_once) | |
| elif nextchar == 'n' and string[idx:idx + 4] == 'null': | |
| return None, idx + 4 | |
| elif nextchar == 't' and string[idx:idx + 4] == 'true': | |
| return True, idx + 4 | |
| elif nextchar == 'f' and string[idx:idx + 5] == 'false': | |
| return False, idx + 5 | |
| m = match_number(string, idx) | |
| if m is not None: | |
| integer, frac, exp = m.groups() | |
| if frac or exp: | |
| res = parse_float(integer + (frac or '') + (exp or '')) | |
| else: | |
| res = parse_int(integer) | |
| return res, m.end() | |
| elif nextchar == 'N' and string[idx:idx + 3] == 'NaN': | |
| return parse_constant('NaN'), idx + 3 | |
| elif nextchar == 'I' and string[idx:idx + 8] == 'Infinity': | |
| return parse_constant('Infinity'), idx + 8 | |
| elif nextchar == '-' and string[idx:idx + 9] == '-Infinity': | |
| return parse_constant('-Infinity'), idx + 9 | |
| else: | |
| raise StopIteration(idx) | |
| def scan_once(string, idx): | |
| try: | |
| return _scan_once(string, idx) | |
| finally: | |
| memo.clear() | |
| return scan_once | |
| make_scanner = c_make_scanner or py_make_scanner | |