| """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 |
| |
| def _scan_once(string, idx): |
| try: |
| nextchar = string[idx] |
| except IndexError: |
| raise StopIteration |
| |
| 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) |
| 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 |
| |
| return _scan_once |
| |
| make_scanner = c_make_scanner or py_make_scanner |