Re: [review] [STLInterfaces] STLInterfaces iterator_interface mini mini review

From: Arthur Gruzauskas (grattle_at_[hidden])
Date: 2019-12-18 06:47:16

On Wednesday, 18 December 2019 1:24:21 PM AEDT Zach Laine via Boost wrote:

[snip] 
> > My one small concern is in the required method:
> > 
> > constexpr auto operator-(repeated_chars_iterator other) const noexcept
> > 
> > instead of:
> > 
> > constexpr auto operator-(const repeated_chars_iterator& other) const
> > noexcept
> > 
> 
> In short, I'm doing this for two reasons:
> 
> 1) An iterator type is typically the size of a pointer or maybe two, and so
> pass-by-value is usually more optimal than pass-by-reference.
> 2) All the STL interfaces that take iterators do it this way, and so making
> the STLInterfaces usage pass-by-reference probably won't affect >= 90% of
> your uses of a given iterator type.
> 
> Zach
> 

I had not thought about the need for an iterator to be lightweight before...

A revisiting of some standard STL algorithms implies copying iterators should 
be quick so as to not impinge on the algorithms' performance.

Both 1) & 2) make sense. 

I withdraw my small concern.

Arthur, who now only likes lightweight iterators