[swift-evolution] [Review] SE-0023 API Design Guidelines (when to use properties)

[Joseph Lord]

On 27/01/2016 23:50, Dave Abrahams via swift-evolution wrote:
>
> on Wed Jan 27 2016, Howard Lovatt <howard.lovatt-AT-gmail.com> wrote:
>
>> I would say that if it doesn't have arguments and doesn't mutate then it
>> should be a property, since it will read better and is flexible (you can
>> switch between a stored and calculated property without affecting the
>> external interface easily).
>
> We had at least one member of the guidelines group initially felt *very*
> strongly that we should use (basically) that criterion.  But then, in
> our survey of the standard library, we found that applying it left us
> with many properties that he wasn't comfortable with, such as
> `sequence.iterator` (today's `sequence.generate()`).

I think that if you get a new instance of something back that will be 
distinct from the one you will get if you access it again then it should 
be a method and not a property. In a way the state has changed because 
it won't give you the same instance. This would keep generate() in the 
method category (for single use ones anyway).

Joseph