Remove SliceConcatExt, add them as methods on [T].

[bluss]

Remove SliceConcatExt, add them as methods on [T].

We don't need extension traits for this anymore.

[gkoz]

Related PR: Rename connect to join.

BTW I'd very much like Iterator to have those methods instead. I know that would be less efficient than the current implementation. Maybe impl Iterator for slice::Iter could still salvage the more efficient implementation.

[bluss]

Moving a method from an unstable trait to an inherent impl is a minor breaking change I guess.

This quirky stuff compiles because concat is on a prelude trait:

<_>::concat(&["1", "2"][..])

[frewsxcv]

Here's how Servo joins strings. It's nice that it works directly with iterators to avoid unnecessary allocations

[gkoz]

@frewsxcv
Is push_str in that implementation not performing any reallocations? Ones that SliceConcatExt is avoiding?

[bluss]

Right, the slice version avoids reallocation while building the string by iterating through to sum up the exact capacity needed up front.

[frewsxcv]

I meant that if I have some other data structure like a HashSet, I'd have to iterate through all the string and collect them (causing an allocation to occur I think?) before calling join on it

[bluss]

Yes. Notice that servo could use SliceConcatExt's join when it has a slice for a much more efficient join operation. It's only unfortunate that we can't offer both the efficient slice version and the less efficient iterator version in a single method call. Specialization could help.