1 """JSON token scanner 2 """ 3 import re 4 try: 5 from _json import make_scanner as c_make_scanner 6 except ImportError: 7 c_make_scanner = None 8 9 __all__ = ['make_scanner'] 10 11 NUMBER_RE = re.compile( 12 r'(-?(?:0|[1-9]\d*))(\.\d+)?([eE][-+]?\d+)?', 13 (re.VERBOSE | re.MULTILINE | re.DOTALL)) 14 15 def py_make_scanner(context): 16 parse_object = context.parse_object 17 parse_array = context.parse_array 18 parse_string = context.parse_string 19 match_number = NUMBER_RE.match 20 encoding = context.encoding 21 strict = context.strict 22 parse_float = context.parse_float 23 parse_int = context.parse_int 24 parse_constant = context.parse_constant 25 object_hook = context.object_hook 26 object_pairs_hook = context.object_pairs_hook 27 28 def _scan_once(string, idx): 29 try: 30 nextchar = string[idx] 31 except IndexError: 32 raise StopIteration 33 34 if nextchar == '"': 35 return parse_string(string, idx + 1, encoding, strict) 36 elif nextchar == '{': 37 return parse_object((string, idx + 1), encoding, strict, 38 _scan_once, object_hook, object_pairs_hook) 39 elif nextchar == '[': 40 return parse_array((string, idx + 1), _scan_once) 41 elif nextchar == 'n' and string[idx:idx + 4] == 'null': 42 return None, idx + 4 43 elif nextchar == 't' and string[idx:idx + 4] == 'true': 44 return True, idx + 4 45 elif nextchar == 'f' and string[idx:idx + 5] == 'false': 46 return False, idx + 5 47 48 m = match_number(string, idx) 49 if m is not None: 50 integer, frac, exp = m.groups() 51 if frac or exp: 52 res = parse_float(integer + (frac or '') + (exp or '')) 53 else: 54 res = parse_int(integer) 55 return res, m.end() 56 elif nextchar == 'N' and string[idx:idx + 3] == 'NaN': 57 return parse_constant('NaN'), idx + 3 58 elif nextchar == 'I' and string[idx:idx + 8] == 'Infinity': 59 return parse_constant('Infinity'), idx + 8 60 elif nextchar == '-' and string[idx:idx + 9] == '-Infinity': 61 return parse_constant('-Infinity'), idx + 9 62 else: 63 raise StopIteration 64 65 return _scan_once 66 67 make_scanner = c_make_scanner or py_make_scanner 68
