diff options
Diffstat (limited to 'Doc/library/numbers.rst')
| -rw-r--r-- | Doc/library/numbers.rst | 34 |
1 files changed, 17 insertions, 17 deletions
diff --git a/Doc/library/numbers.rst b/Doc/library/numbers.rst index b3dce15..2a05b56 100644 --- a/Doc/library/numbers.rst +++ b/Doc/library/numbers.rst @@ -160,23 +160,23 @@ refer to ``MyIntegral`` and ``OtherTypeIKnowAbout`` as of :class:`Complex` (``a : A <: Complex``), and ``b : B <: Complex``. I'll consider ``a + b``: - 1. If ``A`` defines an :meth:`__add__` which accepts ``b``, all is - well. - 2. If ``A`` falls back to the boilerplate code, and it were to - return a value from :meth:`__add__`, we'd miss the possibility - that ``B`` defines a more intelligent :meth:`__radd__`, so the - boilerplate should return :const:`NotImplemented` from - :meth:`__add__`. (Or ``A`` may not implement :meth:`__add__` at - all.) - 3. Then ``B``'s :meth:`__radd__` gets a chance. If it accepts - ``a``, all is well. - 4. If it falls back to the boilerplate, there are no more possible - methods to try, so this is where the default implementation - should live. - 5. If ``B <: A``, Python tries ``B.__radd__`` before - ``A.__add__``. This is ok, because it was implemented with - knowledge of ``A``, so it can handle those instances before - delegating to :class:`Complex`. +1. If ``A`` defines an :meth:`__add__` which accepts ``b``, all is + well. +2. If ``A`` falls back to the boilerplate code, and it were to + return a value from :meth:`__add__`, we'd miss the possibility + that ``B`` defines a more intelligent :meth:`__radd__`, so the + boilerplate should return :const:`NotImplemented` from + :meth:`__add__`. (Or ``A`` may not implement :meth:`__add__` at + all.) +3. Then ``B``'s :meth:`__radd__` gets a chance. If it accepts + ``a``, all is well. +4. If it falls back to the boilerplate, there are no more possible + methods to try, so this is where the default implementation + should live. +5. If ``B <: A``, Python tries ``B.__radd__`` before + ``A.__add__``. This is ok, because it was implemented with + knowledge of ``A``, so it can handle those instances before + delegating to :class:`Complex`. If ``A <: Complex`` and ``B <: Real`` without sharing any other knowledge, then the appropriate shared operation is the one involving the built |