either

[Justin Johansson]

On 12/01/11 06:28, KennyTM~ wrote:
> On Jan 11, 11 17:10, Justin Johansson wrote:
>> On 10/01/11 05:42, Andrei Alexandrescu wrote:
>>> I wrote a simple helper, in spirit with some recent discussions:
>>> unittest
>>> {
>>> assert(1 == either(1, 2, 3));
>>> assert(4 != either(1, 2, 3));
>>> assert("abac" != either("aasd", "s"));
>>> assert("abac" == either("aasd", "abac", "s"));
>>> }
>>>
>> Just my 2 cents and I wonder if there some other way of achieving the
>> desired functionality of your helper without resorting to overloading
>> "==" and the consequential violation of the commonly held semantics of
>> equality.
>>
> We could use in instead of ==
>
> if (1 in oneOf(1, 2, 3)) { ... }
> if (4 !in oneOf(1, 2, 3)) { ... }

Nice suggestion.

At the end of the day though it basically boils down to having either a 
binary operator** or a function for it.

(** preferably excluding "==" and other undesirable operator overloads 
of course).