diff options
Diffstat (limited to 'Lib/operator.py')
-rw-r--r-- | Lib/operator.py | 412 |
1 files changed, 412 insertions, 0 deletions
diff --git a/Lib/operator.py b/Lib/operator.py new file mode 100644 index 0000000..ee81266 --- /dev/null +++ b/Lib/operator.py @@ -0,0 +1,412 @@ +#!/usr/bin/env python3 +""" +Operator Interface + +This module exports a set of functions corresponding to the intrinsic +operators of Python. For example, operator.add(x, y) is equivalent +to the expression x+y. The function names are those used for special +methods; variants without leading and trailing '__' are also provided +for convenience. + +This is the pure Python implementation of the module. +""" + +__all__ = ['abs', 'add', 'and_', 'attrgetter', 'concat', 'contains', 'countOf', + 'delitem', 'eq', 'floordiv', 'ge', 'getitem', 'gt', 'iadd', 'iand', + 'iconcat', 'ifloordiv', 'ilshift', 'imod', 'imul', 'index', + 'indexOf', 'inv', 'invert', 'ior', 'ipow', 'irshift', 'is_', + 'is_not', 'isub', 'itemgetter', 'itruediv', 'ixor', 'le', + 'length_hint', 'lshift', 'lt', 'methodcaller', 'mod', 'mul', 'ne', + 'neg', 'not_', 'or_', 'pos', 'pow', 'rshift', 'setitem', 'sub', + 'truediv', 'truth', 'xor'] + +from builtins import abs as _abs + + +# Comparison Operations *******************************************************# + +def lt(a, b): + "Same as a < b." + return a < b + +def le(a, b): + "Same as a <= b." + return a <= b + +def eq(a, b): + "Same as a == b." + return a == b + +def ne(a, b): + "Same as a != b." + return a != b + +def ge(a, b): + "Same as a >= b." + return a >= b + +def gt(a, b): + "Same as a > b." + return a > b + +# Logical Operations **********************************************************# + +def not_(a): + "Same as not a." + return not a + +def truth(a): + "Return True if a is true, False otherwise." + return True if a else False + +def is_(a, b): + "Same as a is b." + return a is b + +def is_not(a, b): + "Same as a is not b." + return a is not b + +# Mathematical/Bitwise Operations *********************************************# + +def abs(a): + "Same as abs(a)." + return _abs(a) + +def add(a, b): + "Same as a + b." + return a + b + +def and_(a, b): + "Same as a & b." + return a & b + +def floordiv(a, b): + "Same as a // b." + return a // b + +def index(a): + "Same as a.__index__()." + return a.__index__() + +def inv(a): + "Same as ~a." + return ~a +invert = inv + +def lshift(a, b): + "Same as a << b." + return a << b + +def mod(a, b): + "Same as a % b." + return a % b + +def mul(a, b): + "Same as a * b." + return a * b + +def neg(a): + "Same as -a." + return -a + +def or_(a, b): + "Same as a | b." + return a | b + +def pos(a): + "Same as +a." + return +a + +def pow(a, b): + "Same as a ** b." + return a ** b + +def rshift(a, b): + "Same as a >> b." + return a >> b + +def sub(a, b): + "Same as a - b." + return a - b + +def truediv(a, b): + "Same as a / b." + return a / b + +def xor(a, b): + "Same as a ^ b." + return a ^ b + +# Sequence Operations *********************************************************# + +def concat(a, b): + "Same as a + b, for a and b sequences." + if not hasattr(a, '__getitem__'): + msg = "'%s' object can't be concatenated" % type(a).__name__ + raise TypeError(msg) + return a + b + +def contains(a, b): + "Same as b in a (note reversed operands)." + return b in a + +def countOf(a, b): + "Return the number of times b occurs in a." + count = 0 + for i in a: + if i == b: + count += 1 + return count + +def delitem(a, b): + "Same as del a[b]." + del a[b] + +def getitem(a, b): + "Same as a[b]." + return a[b] + +def indexOf(a, b): + "Return the first index of b in a." + for i, j in enumerate(a): + if j == b: + return i + else: + raise ValueError('sequence.index(x): x not in sequence') + +def setitem(a, b, c): + "Same as a[b] = c." + a[b] = c + +def length_hint(obj, default=0): + """ + Return an estimate of the number of items in obj. + This is useful for presizing containers when building from an iterable. + + If the object supports len(), the result will be exact. Otherwise, it may + over- or under-estimate by an arbitrary amount. The result will be an + integer >= 0. + """ + if not isinstance(default, int): + msg = ("'%s' object cannot be interpreted as an integer" % + type(default).__name__) + raise TypeError(msg) + + try: + return len(obj) + except TypeError: + pass + + try: + hint = type(obj).__length_hint__ + except AttributeError: + return default + + try: + val = hint(obj) + except TypeError: + return default + if val is NotImplemented: + return default + if not isinstance(val, int): + msg = ('__length_hint__ must be integer, not %s' % + type(val).__name__) + raise TypeError(msg) + if val < 0: + msg = '__length_hint__() should return >= 0' + raise ValueError(msg) + return val + +# Generalized Lookup Objects **************************************************# + +class attrgetter: + """ + Return a callable object that fetches the given attribute(s) from its operand. + After f=attrgetter('name'), the call f(r) returns r.name. + After g=attrgetter('name', 'date'), the call g(r) returns (r.name, r.date). + After h=attrgetter('name.first', 'name.last'), the call h(r) returns + (r.name.first, r.name.last). + """ + def __init__(self, attr, *attrs): + if not attrs: + if not isinstance(attr, str): + raise TypeError('attribute name must be a string') + names = attr.split('.') + def func(obj): + for name in names: + obj = getattr(obj, name) + return obj + self._call = func + else: + getters = tuple(map(attrgetter, (attr,) + attrs)) + def func(obj): + return tuple(getter(obj) for getter in getters) + self._call = func + + def __call__(self, obj): + return self._call(obj) + +class itemgetter: + """ + Return a callable object that fetches the given item(s) from its operand. + After f=itemgetter(2), the call f(r) returns r[2]. + After g=itemgetter(2,5,3), the call g(r) returns (r[2], r[5], r[3]) + """ + def __init__(self, item, *items): + if not items: + def func(obj): + return obj[item] + self._call = func + else: + items = (item,) + items + def func(obj): + return tuple(obj[i] for i in items) + self._call = func + + def __call__(self, obj): + return self._call(obj) + +class methodcaller: + """ + Return a callable object that calls the given method on its operand. + After f = methodcaller('name'), the call f(r) returns r.name(). + After g = methodcaller('name', 'date', foo=1), the call g(r) returns + r.name('date', foo=1). + """ + + def __init__(*args, **kwargs): + if len(args) < 2: + msg = "methodcaller needs at least one argument, the method name" + raise TypeError(msg) + self = args[0] + self._name = args[1] + self._args = args[2:] + self._kwargs = kwargs + + def __call__(self, obj): + return getattr(obj, self._name)(*self._args, **self._kwargs) + +# In-place Operations *********************************************************# + +def iadd(a, b): + "Same as a += b." + a += b + return a + +def iand(a, b): + "Same as a &= b." + a &= b + return a + +def iconcat(a, b): + "Same as a += b, for a and b sequences." + if not hasattr(a, '__getitem__'): + msg = "'%s' object can't be concatenated" % type(a).__name__ + raise TypeError(msg) + a += b + return a + +def ifloordiv(a, b): + "Same as a //= b." + a //= b + return a + +def ilshift(a, b): + "Same as a <<= b." + a <<= b + return a + +def imod(a, b): + "Same as a %= b." + a %= b + return a + +def imul(a, b): + "Same as a *= b." + a *= b + return a + +def ior(a, b): + "Same as a |= b." + a |= b + return a + +def ipow(a, b): + "Same as a **= b." + a **=b + return a + +def irshift(a, b): + "Same as a >>= b." + a >>= b + return a + +def isub(a, b): + "Same as a -= b." + a -= b + return a + +def itruediv(a, b): + "Same as a /= b." + a /= b + return a + +def ixor(a, b): + "Same as a ^= b." + a ^= b + return a + + +try: + from _operator import * +except ImportError: + pass +else: + from _operator import __doc__ + +# All of these "__func__ = func" assignments have to happen after importing +# from _operator to make sure they're set to the right function +__lt__ = lt +__le__ = le +__eq__ = eq +__ne__ = ne +__ge__ = ge +__gt__ = gt +__not__ = not_ +__abs__ = abs +__add__ = add +__and__ = and_ +__floordiv__ = floordiv +__index__ = index +__inv__ = inv +__invert__ = invert +__lshift__ = lshift +__mod__ = mod +__mul__ = mul +__neg__ = neg +__or__ = or_ +__pos__ = pos +__pow__ = pow +__rshift__ = rshift +__sub__ = sub +__truediv__ = truediv +__xor__ = xor +__concat__ = concat +__contains__ = contains +__delitem__ = delitem +__getitem__ = getitem +__setitem__ = setitem +__iadd__ = iadd +__iand__ = iand +__iconcat__ = iconcat +__ifloordiv__ = ifloordiv +__ilshift__ = ilshift +__imod__ = imod +__imul__ = imul +__ior__ = ior +__ipow__ = ipow +__irshift__ = irshift +__isub__ = isub +__itruediv__ = itruediv +__ixor__ = ixor |