On 5/12/10, Colin Bartlett <colinb2r / googlemail.com> wrote:
> With a pedantic former maths student's hat on:
> If you return self first and then other:
>   + will (probably?) work because (almost?) all uses of + are commutative
>    (I've never seen a non-commutative use of +, but you never know!);
>   * will probably work, but may not if the use of * is not commutative
>    (for example matrix multiplication?);
>   - and / and ** (probably?) won't work because (almost?) all uses of them
>    are non-commutative. (I've never seen commutative uses, but ...);
>   and if <=> is defined for (a representation of) other and
>     (a representation of) self, that probably won't work either!

Ah, thanks I knew there was an appropriate vocab word I was forgetting
and it was commutative. I think your elaboration (above) is a great
deal clearer than mine.