[swift-evolution] Proposal: Implement == and < for tuples where possible, up to some high arity

[Dmitri Gribenko]

On Mon, Dec 7, 2015 at 4:17 PM, Brent Royal-Gordon
<brent at architechies.com> wrote:
>>>>      return zip([a1,b1,c1,d1,e1], [a2,b2,c2,d2,e2]).lazy.filter(==).first.flatMap(<) ?? false
>>>>
>>>> Okay, so that wasn’t quite as easy as I thought when I started writing
>>>> the email.
>>>
>>> That also allocates two intermediate arrays (the inputs to zip()).
>>
>> And relies on all variables having the same type.
>
> Both true. What actually happened was, when I looked at the tuple version, I thought “okay, that’s basically just zipping the two together and then running < on each pair". In trying to write the email making that point, I discovered that this “easy” alternative is actually ridiculously complicated once you translate it from a vague notion to running code, and thought that was funny.

We have lexicographicalCompare(), so it is not that complicated after all.

Dmitri

-- 
main(i,j){for(i=2;;i++){for(j=2;j<i;j++){if(!(i%j)){j=0;break;}}if
(j){printf("%d\n",i);}}} /*Dmitri Gribenko <gribozavr at gmail.com>*/