Jingwen Chen | 475b3cc | 2021-01-05 21:45:16 -0500 | [diff] [blame] | 1 | """Redo the builtin repr() (representation) but with limits on most sizes.""" |
| 2 | |
| 3 | __all__ = ["Repr", "repr", "recursive_repr"] |
| 4 | |
| 5 | import builtins |
| 6 | from itertools import islice |
| 7 | from _thread import get_ident |
| 8 | |
| 9 | def recursive_repr(fillvalue='...'): |
| 10 | 'Decorator to make a repr function return fillvalue for a recursive call' |
| 11 | |
| 12 | def decorating_function(user_function): |
| 13 | repr_running = set() |
| 14 | |
| 15 | def wrapper(self): |
| 16 | key = id(self), get_ident() |
| 17 | if key in repr_running: |
| 18 | return fillvalue |
| 19 | repr_running.add(key) |
| 20 | try: |
| 21 | result = user_function(self) |
| 22 | finally: |
| 23 | repr_running.discard(key) |
| 24 | return result |
| 25 | |
| 26 | # Can't use functools.wraps() here because of bootstrap issues |
| 27 | wrapper.__module__ = getattr(user_function, '__module__') |
| 28 | wrapper.__doc__ = getattr(user_function, '__doc__') |
| 29 | wrapper.__name__ = getattr(user_function, '__name__') |
| 30 | wrapper.__qualname__ = getattr(user_function, '__qualname__') |
| 31 | wrapper.__annotations__ = getattr(user_function, '__annotations__', {}) |
| 32 | return wrapper |
| 33 | |
| 34 | return decorating_function |
| 35 | |
| 36 | class Repr: |
| 37 | |
| 38 | def __init__(self): |
| 39 | self.maxlevel = 6 |
| 40 | self.maxtuple = 6 |
| 41 | self.maxlist = 6 |
| 42 | self.maxarray = 5 |
| 43 | self.maxdict = 4 |
| 44 | self.maxset = 6 |
| 45 | self.maxfrozenset = 6 |
| 46 | self.maxdeque = 6 |
| 47 | self.maxstring = 30 |
| 48 | self.maxlong = 40 |
| 49 | self.maxother = 30 |
| 50 | |
| 51 | def repr(self, x): |
| 52 | return self.repr1(x, self.maxlevel) |
| 53 | |
| 54 | def repr1(self, x, level): |
| 55 | typename = type(x).__name__ |
| 56 | if ' ' in typename: |
| 57 | parts = typename.split() |
| 58 | typename = '_'.join(parts) |
| 59 | if hasattr(self, 'repr_' + typename): |
| 60 | return getattr(self, 'repr_' + typename)(x, level) |
| 61 | else: |
| 62 | return self.repr_instance(x, level) |
| 63 | |
| 64 | def _repr_iterable(self, x, level, left, right, maxiter, trail=''): |
| 65 | n = len(x) |
| 66 | if level <= 0 and n: |
| 67 | s = '...' |
| 68 | else: |
| 69 | newlevel = level - 1 |
| 70 | repr1 = self.repr1 |
| 71 | pieces = [repr1(elem, newlevel) for elem in islice(x, maxiter)] |
| 72 | if n > maxiter: pieces.append('...') |
| 73 | s = ', '.join(pieces) |
| 74 | if n == 1 and trail: right = trail + right |
| 75 | return '%s%s%s' % (left, s, right) |
| 76 | |
| 77 | def repr_tuple(self, x, level): |
| 78 | return self._repr_iterable(x, level, '(', ')', self.maxtuple, ',') |
| 79 | |
| 80 | def repr_list(self, x, level): |
| 81 | return self._repr_iterable(x, level, '[', ']', self.maxlist) |
| 82 | |
| 83 | def repr_array(self, x, level): |
| 84 | if not x: |
| 85 | return "array('%s')" % x.typecode |
| 86 | header = "array('%s', [" % x.typecode |
| 87 | return self._repr_iterable(x, level, header, '])', self.maxarray) |
| 88 | |
| 89 | def repr_set(self, x, level): |
| 90 | if not x: |
| 91 | return 'set()' |
| 92 | x = _possibly_sorted(x) |
| 93 | return self._repr_iterable(x, level, '{', '}', self.maxset) |
| 94 | |
| 95 | def repr_frozenset(self, x, level): |
| 96 | if not x: |
| 97 | return 'frozenset()' |
| 98 | x = _possibly_sorted(x) |
| 99 | return self._repr_iterable(x, level, 'frozenset({', '})', |
| 100 | self.maxfrozenset) |
| 101 | |
| 102 | def repr_deque(self, x, level): |
| 103 | return self._repr_iterable(x, level, 'deque([', '])', self.maxdeque) |
| 104 | |
| 105 | def repr_dict(self, x, level): |
| 106 | n = len(x) |
| 107 | if n == 0: return '{}' |
| 108 | if level <= 0: return '{...}' |
| 109 | newlevel = level - 1 |
| 110 | repr1 = self.repr1 |
| 111 | pieces = [] |
| 112 | for key in islice(_possibly_sorted(x), self.maxdict): |
| 113 | keyrepr = repr1(key, newlevel) |
| 114 | valrepr = repr1(x[key], newlevel) |
| 115 | pieces.append('%s: %s' % (keyrepr, valrepr)) |
| 116 | if n > self.maxdict: pieces.append('...') |
| 117 | s = ', '.join(pieces) |
| 118 | return '{%s}' % (s,) |
| 119 | |
| 120 | def repr_str(self, x, level): |
| 121 | s = builtins.repr(x[:self.maxstring]) |
| 122 | if len(s) > self.maxstring: |
| 123 | i = max(0, (self.maxstring-3)//2) |
| 124 | j = max(0, self.maxstring-3-i) |
| 125 | s = builtins.repr(x[:i] + x[len(x)-j:]) |
| 126 | s = s[:i] + '...' + s[len(s)-j:] |
| 127 | return s |
| 128 | |
| 129 | def repr_int(self, x, level): |
| 130 | s = builtins.repr(x) # XXX Hope this isn't too slow... |
| 131 | if len(s) > self.maxlong: |
| 132 | i = max(0, (self.maxlong-3)//2) |
| 133 | j = max(0, self.maxlong-3-i) |
| 134 | s = s[:i] + '...' + s[len(s)-j:] |
| 135 | return s |
| 136 | |
| 137 | def repr_instance(self, x, level): |
| 138 | try: |
| 139 | s = builtins.repr(x) |
| 140 | # Bugs in x.__repr__() can cause arbitrary |
| 141 | # exceptions -- then make up something |
| 142 | except Exception: |
| 143 | return '<%s instance at %#x>' % (x.__class__.__name__, id(x)) |
| 144 | if len(s) > self.maxother: |
| 145 | i = max(0, (self.maxother-3)//2) |
| 146 | j = max(0, self.maxother-3-i) |
| 147 | s = s[:i] + '...' + s[len(s)-j:] |
| 148 | return s |
| 149 | |
| 150 | |
| 151 | def _possibly_sorted(x): |
| 152 | # Since not all sequences of items can be sorted and comparison |
| 153 | # functions may raise arbitrary exceptions, return an unsorted |
| 154 | # sequence in that case. |
| 155 | try: |
| 156 | return sorted(x) |
| 157 | except Exception: |
| 158 | return list(x) |
| 159 | |
| 160 | aRepr = Repr() |
| 161 | repr = aRepr.repr |