Comparing Multiple Values (the story so far/summary)

[downs]

Bill Baxter wrote:
> BCS wrote:
>> Reply to Downs,
>>
>>> Bill Baxter wrote:
>>>
>>>> downs wrote:
>>>>
>>>>>
>>>>> `in` already is an infix operator :)
>>>>>
>>>>> --downs
>>>>>
>>>> Yes, but it doesn't work!
>>>>
>>>> --bb
>>>>
>>> Curious.
>>>
>>> Works here, GDC 1.028 / 4.1.2
>>>
>>> What are you using?
>>>
>>> --downs
>>>
>>
>> I think he was saying the "in" operator dosn't work / works wrong. 
> 
> Right, as in "a in [1,2,3]"  is an error, rather than doing what the
> poster who started this thread expected it to do.
> 

To give an example of W's stance ..

Say you have a book with four pages.

The first page contains the number 15, the second page 16 the third 23 and the fourth 42.

Now, if I ask "3 in book", do I mean "is the page 3 in the book" (index) or "is the number 3 in the book" (value)?

There's precedence in the D language for the first case, because `in` for AAs also checks against index (key) and not value.

However, checking against value would arguably be more useful :)

In the absence of a consensus, and because a case could be made for both possibilities, it was decided to leave it out for now.

That should about sum it up.

 --downs