Coverage for Lib/json/scanner.py: 100%

1"""JSON token scanner 

2""" 

3import re 

4try: 

5 from _json import make_scanner as c_make_scanner 

6except ImportError: 

7 c_make_scanner = None 

8 

9__all__ = ['make_scanner'] 

10 

11NUMBER_RE = re.compile( 

12 r'(-?(?:0|[1-9]\d*))(\.\d+)?([eE][-+]?\d+)?', 

13 (re.VERBOSE | re.MULTILINE | re.DOTALL)) 

14 

15def 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 strict = context.strict 

21 parse_float = context.parse_float 

22 parse_int = context.parse_int 

23 parse_constant = context.parse_constant 

24 object_hook = context.object_hook 

25 object_pairs_hook = context.object_pairs_hook 

26 memo = context.memo 

27 

28 def _scan_once(string, idx): 

29 try: 

30 nextchar = string[idx] 

31 except IndexError: 

32 raise StopIteration(idx) from None 

33 

34 if nextchar == '"': 

35 return parse_string(string, idx + 1, strict) 

36 elif nextchar == '{': 

37 return parse_object((string, idx + 1), strict, 

38 _scan_once, object_hook, object_pairs_hook, memo) 

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(idx) 

64 

65 def scan_once(string, idx): 

66 try: 

67 return _scan_once(string, idx) 

68 finally: 

69 memo.clear() 

70 

71 return scan_once 

72 

73make_scanner = c_make_scanner or py_make_scanner