std::ranges::find_if permits use of a sentinel instead of a full
iterator, and supports std::ranges::find as an alternative to certain
simple uses of std::find_if.
Where possible, use the form that takes a range, rather than the form
that takes two iterators.
Add a declared, but not defined, default constructor for
self_return_iterator to satisfy the standard library's concept
`semiregular`, which insists that sentinels be default-constructible,
even for those functions that never need to do so.
Add a defined, but unused, operator++(postfix) for zip_iterator to
satisfy a standard library concept for `forward_iterator`.
Players are not robots, but the show-path cheat tried to pretend they
are, and triggered a BUG warning[1] when looking up robot information
from the player object. Fix this by passing in the robot_info when the
caller is providing a robot, and a named `nullptr` value (as
`create_path_unused_robot_info`) when the caller is providing a
non-robot object.
[1] As below, but repeated many times
```
similar/main/ai.cpp:1905: BUG: object 0x555555858550 has type 4, expected 2
similar/main/ai.cpp:1974: BUG: object 0x555555858550 has type 4, expected 2
```
clang treats names introduced by structured bindings specially, and
refuses to capture them for a lambda, even when it should be capturing
an rvalue reference. gcc accepts this capture.
Switch to initializing a lambda local variable from the structured
binding in the outer scope, which works with both compilers.
Reported-by: Kreeblah <https://github.com/dxx-rebirth/dxx-rebirth/issues/609>
If object creation fails, the counter is not decreased. This creates an
imbalance by over counting the number of robots in existence. Avoid
this imbalance by deferring the counter update until after the robot is
created.
The number of robots accumulated in a game is a function of the the
game's levels, not any particular player. Move it to
d_game_unique_state and rename it to accumulated_robots.
The number of robots accumulated on a level is a function of the level,
not any particular player. Move it to d_level_unique_object_state and
rename it to accumulated_robots.