Is [] mandatory for array operations?

[Robert Jacques]

On Thu, 06 May 2010 14:40:17 -0400, bearophile <bearophileHUGS at lycos.com>  
wrote:
> Kagamin:
>> Since sin's result is not an array,<
>
> I am not sure, but I presume here Don was talking about a dispatch of  
> the sin to all items of an array, so its result is another (new or  
> mutated in place) array.
>
> Bye,
> bearophile
>

That presumes a transform of the form: sin(y[]) => map!sin(y). However,  
this creates unnecessary temporaries which are one of the main things  
array ops is supposed to avoid. So this is a vote against sin(y[])[].

Also, if sin(y[]) returned a lazy/eager array then auto t = sin(y[]);  
should be valid, but auto t = x[] + y[] is not currently valid. So this is  
a vote against sin(y[])[].

As a related note, what do people think of array ops for generic ranges  
(assuming they support length, etc)?