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author | Guido van Rossum <guido@python.org> | 2016-08-15 15:06:38 -0700 |
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committer | Guido van Rossum <guido@python.org> | 2016-08-15 15:06:38 -0700 |
commit | 5130eaed1113f9c0cf99c001fb090901d19a1045 (patch) | |
tree | eef93220ea73656ef2b0b016b6829c166db0b316 /Doc/library/typing.rst | |
parent | 5c15a2e55aab20ed18b890a67ae085c8a73aca11 (diff) | |
download | cpython-5130eaed1113f9c0cf99c001fb090901d19a1045.tar.gz |
Add docs for typing.AnyStr and typing.Text. By Michael Lee.
Diffstat (limited to 'Doc/library/typing.rst')
-rw-r--r-- | Doc/library/typing.rst | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/Doc/library/typing.rst b/Doc/library/typing.rst index c982a7fae1..bc71e1e840 100644 --- a/Doc/library/typing.rst +++ b/Doc/library/typing.rst @@ -647,6 +647,33 @@ The module defines the following classes, functions and decorators: yield start start += 1 +.. class:: AnyStr + + ``AnyStr`` is a type variable defined as + ``AnyStr = TypeVar('AnyStr', str, bytes)``. + + It is meant to be used for functions that may accept any kind of string + without allowing different kinds of strings to mix. For example:: + + def concat(a: AnyStr, b: AnyStr) -> AnyStr: + return a + b + + concat(u"foo", u"bar") # Ok, output has type 'unicode' + concat(b"foo", b"bar") # Ok, output has type 'bytes' + concat(u"foo", b"bar") # Error, cannot mix unicode and bytes + +.. class:: Text + + ``Text`` is an alias for ``str``. It is provided to supply a forward + compatible path for Python 2 code: in Python 2, ``Text`` is an alias for + ``unicode``. + + Use ``Text`` to indicate that a value must contain a unicode string in + a manner that is compatible with both Python 2 and Python 3:: + + def add_unicode_checkmark(text: Text) -> Text: + return text + u' \u2713' + .. class:: io Wrapper namespace for I/O stream types. |