P2187R4 std::swap_if, std::predictable (Nathan Myers)

P2187R5 std::swap_if, std::predictable (Nathan Myers)

2020-10-19 Library Evolution Mailing List Review

I believe we want at least one piece of this: swap_if.

Specifying a specific overload for swap_if on trivially relocatable or cheaply swappable types does not seem like an essential feature of swap_if to specify. It can be quality of implementation; it can be extended later when we have P1144.

I've not heard as much discussion or support for predictable.

Based on this discussion, this paper should be revised as follows:

• Remove is_trivially_swappable, etc; leave a section in mentioning it as a possible future extension once P1144 has advanced.
• Don't try to specify a particular implementation strategy for swap_if: until we have something like P1144, it can just be QoI.
• Remove predictable. Perhaps separate it into a separate paper, if you feel strongly about it, but there is greater consensus and interest in swap_if than there is for predictable.

Closing due to more than 1 year of inactivity. Please re-open if further work is expected.