Consider making n4::ui::apply_cli_{early,late} implicit

[jacg]

Requiring the user to write them explicitly only provides some extra hoops to jump through and gives the opportunity to make a mistake.

The only reason for having them explicit is to allow injection of apply_command and apply_{early_late}_macro both before and after the CLI args. Is this genuinely useful? Is it worth the extra complexity for the client?

[gonzaponte]

The other point was that it would help the user understand exactly when each command/macro is executed. If we ignore apply_command, this can probably be described thoroughly in the documentation and might be enough.

apply_command is a general utility that provides a lot of flexibility, but

• it probably has very little use in realistic cases
• goes against the philosophy of macros. Macros allow you to turn knobs and switches without recompilation. Using apply_command requires recompilation.

There might be some cases that I'm not considering where apply_command might be useful, but I think those can always be solved by using macros.

[jacg]

• goes against the philosophy of macros. Macros allow you to turn knobs and switches without recompilation. Using apply_command requires recompilation.

I see the point of apply_command as hard-wiring something that is more easily done with macro commands than with C++ source code. In that way, you are not re-compiling any more often than you would be when changing any other behaviour defined in the source code.