https://github.com/simd-everywhere/simde has done their first release ( https://simd-everywhere.github.io/blog/announcements/release/2020/06/21/0.5.0-release.html ) and it seems like something potentially useful for merging code paths. The most likely candidate I imagine is using SIMD code to replace the non-SIMD fallback path, but maybe it'd be worth checking if it can be used to merge ARM and x8

They should take single matcher during construction, and their match method should take a generic range, using the new generic matcher support.

Expected usage:

REQUIRE_THAT(get_keys(), AllMatch(KeyPattern({1, 2, 3})));
REQUIRE_THAT(get_numbers(), NoneMatch(IsOdd{}));
REQUIRE_THAT(get_strings(), AnyMatch(Contains("webscale") && !Contains("MongoDB")));

the matching semantics

The doc is great! Hoewever some areas are still missing.
C++11 intoduced raw string literals: https://en.cppreference.com/w/cpp/language/string_literal

It is useful in many different areas, like strings with quotes, multiline strings and for example windows paths without escaping backslashes:

const char win_path[] = R"(c:\some\unescaped\path)";

The same cppreference link als

Names map and input are exchanged mistakenly. By sense of Preconditions paragraph they have to be exchanged I suppose, because there is no problem when map and result coincide (in current context).

It would be a cool proof of concept to see Flecs running in the browser. As a first step towards this, the ecs_graphics project could be ported as it showcases the bare minimum for a game with graphics (input + rendering).

Link to example:
https://github.com/SanderMertens/ecs_graphics