[Python-Dev] Why not support user defined operator overloading ?
python-dev at masklinn.net
Sun Sep 29 17:06:32 CEST 2013
On 2013-09-29, at 14:51 , 张佩佩 wrote:
> As far as I know, there is not a language support user defined operator overloading.
> Python3 can overloading belowed operators.
> - negated
> + unchanged
> - minus
> + add
> * multiplication
> / division
> // true division
> % remainder
> ** power
> (Do I miss something ?)
~ invert (unary)
. get attribute
 get item
<< left shift
>> right shift
& binary and
| binary or
And the inplace versions of most of these can be implemented separately,
which can probably be counted as supplementary operators.
> If we can overloading these operators, why we can't overloading other operators?
> (like .* often used in matrix, U in set operation)
This is more of a python-ideas subject.
And one of the reasons likely is that it would require significantly
reworking the grammar to handle a kind of user-defined opname (similar
to name, but for operator tokens), with user-defined priority and
associativity, and the ability to import operators (or define how and
when operators become available compared to their definition)
That's a huge amount of complexity with little to gain.
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