py-pattern-matching 0.1.1

用法

使用两个参数调用patternmatching.match（）函数：

• 参数1：要匹配的模式
• 参数2：要匹配的数据结构
• 可选参数flatten: True具有匹配的值 扁平的，即以扁平元组的形式返回，不管其位置如何 在匹配数据的结构中。

返回值：

if flatten is true:
    match_ok, [matched_value, matched_value, matched_value, ...]
if flatten is not true:
    match_ok, matched_data_structure

警告： 如果忽略模式中的所有匹配值，match（）不返回元组，而是返回布尔值。

是的：

match_ok = match(PATTERN, DATA)

否：

match_ok, = match(PATTERN, DATA)

内置匹配对象

• 任何
• 是实例

任何匹配对象都可以用IGNORE()包装以忽略该值 与返回值中的匹配对象匹配。

IGNORE本身可以用作IGNORE(ANY)的快捷方式。

assert True == match(IGNORE, 123)

在（单元）测试中使用（但也在其他任何地方使用）

如果不能比较函数的返回值，则比较起来很繁琐 只需使用=运算符例如，当函数返回 你只关心元组的某些部分而不关心 整个元组：

retval = some_function_under_test()
assert retval and isinstance(retval, tuple) \
    and len(retval) == 3 and retval[0] == 'foo' \
    and isinstance(retval[1], tuple) and len(retval[1]) == 2 \
    and isinstance(retval[1][1], SomeException)

使用模式匹配：

retval = some_function_under_test()
assert retval == ('foo', (ANY, IS_INSTANCE(SomeException)), ANY)

示例

match_ok, value = match(ANY, 'foobar')
assert match_ok and value == 'foobar'

match_ok = match(IGNORE(ANY), 'foobar')
assert match_ok

match_ok, value1, value2 match((ANY, ANY), ('foo', 'bar'))
assert match_ok and value1 == 'foo' and value2 == 'bar'

match_ok, (value1, value2) = match((ANY, ANY), ('foo', 'bar'), flatten=False)
assert match_ok and value1 == 'foo' and value2 == 'bar'

match_ok, (value1, ) = match((ANY, IGNORE(ANY)), ('foo', 'whatev'))
assert match_ok and value1 == 'foo'

match_ok, value1, value2 = match(('foo', ANY, ANY), ('foo', 1, 2))
assert match_ok and value1 == 1 and value2 == 2

match_ok, value1, value2, value3 = match(('foo', ANY, (ANY, ANY)), ('foo', 1, (2, 3)))
assert match_ok and value1 == 1 and value2 == 2 and value3 = 3

match_ok, (value1, (value2, value3)) = match(('foo', ANY, (ANY, ANY)), ('foo', 1, (2, 3)), flatten=False)
assert match_ok and value1 == 1 and value2 == 2 and value3 = 3

match_ok = match(3, 4)
assert not match_ok

# notice how you can still successfully do unpacking of return values and just ignore `value` if the match failed
match_ok, value = match(IS_INSTANCE(unicode), '123132')
assert not match_ok

# notice how you can still successfully do unpacking of return values and just ignore `value` if the match failed
match_ok, (value1, (value2, value3)) = match(('foo', (ANY, (ANY, ANY))), ('not-foo', (1, (2, 3))))
assert not match_ok

# ...even when the structure of the data completely mismatches
match_ok, (value1, (value2, value3)) = match(('foo', (ANY, (ANY, ANY))), ('foo', 'blabla'))
assert not match_ok

# ...don't rely on `value1`, `value2` and `value3` being `None` though--the matcher can still return whatever it wants there; you have to check `match_ok` yourself.