This file contains a simple logging function. It is a modified version of the example logging function implementation provided in `std.log`.

@: *
@= Imports

@= Level setting

@= Logging function
@.

We first import the standard library, and the `Level` type which is an enum representing the possible log levels.

@: Imports
const std = @import("std");
const Level = std.log.Level;
@.

The logging function is structured such that only log messages equal to or above a certain severity threshold will be printed to the console. This threshold can then be globally modified during development. The threshold constant is defined below.

@: Level setting
pub const log_level: Level = .warn;
@.

We then define the logging function itself, which accepts a `Level` value and the format string and argument struct to be passed to the inner print function.

@: Logging function
pub fn log(
    comptime level: Level,
    comptime format: []const u8,
    args: anytype,
) void {
	@= Compare with level threshold

	@= Define message string

	@= Print to console
}
@.

First the comparison against the severity threshold is made. (A lower integer value signifies a higher severity.) If the severity is lower than the threshold, the function immediately exits.

@: Compare with level threshold
if (@enumToInt(level) > @enumToInt(log_level)) return;
@.

Next the message string is created. The unformatted content of this string is evaluated at compile-time, before being formatted by the print function at runtime. The "info" and "error" log levels use custom names, whereas all other levels use their default display names.

@: Define message string
const msg = "[" ++ switch (level) {
        .info => "ok",
        .err => "err",
        else => level.asText(),
} ++ "]\t" ++ format ++ "\n";
@.

Finally, the message is printed to the console. If an error is returned by the `print()` call, the logging function silently exits.

@: Print to console
const stderr = std.io.getStdErr().writer();
nosuspend stderr.print(msg, args) catch return;
@.