!in

[Andrei Alexandrescu]

Pelle Månsson wrote:
> On 02/17/2010 10:25 PM, Andrei Alexandrescu wrote:
>> What evidence do you have that it's widely useful?
> 
> I use it once in a while in python, evidence enough? :)
> 
>> Well I understand you don't agree from the frame you're now in, but you
>> haven't heard my argument yet. Under such conditions you shouldn't say
>> "can't"! Here goes my argument.
>>
>> 1. An array literal has no name and cannot be aliased, hence it's
>> private to the implementation. The implementation is therefore free to
>> induce structure on the searched elements, e.g. by sorting the array or
>> using a hash.
>>
>> 2. The size of an array variable must be conservatively assumed to scale
>> with the size of the input. The size of an array literal scales with the
>> size of the program, or in the worst case (code generation) with
>> statically-known inputs to the program.
> 
> I don't see how this is any argument against opIn_r for array variables 
> as well.
> 
> I mean, the argument against it seems to be to make it more difficult to 
> do a linear search over an array, which seems rather backwards to me.

Not more difficult, but not deceivingly easy either. I like how you can 
search with simple syntax in an associative array but not in a linear array.

Andrei