Zigで小さなアプリを書くときによく使うテンプレ

Arena Allocatorや基本的なstdoutとstderrを使う

const std = @import("std");
const fs = std.fs;
const heap = std.heap;
const mem = std.mem;
const process = std.process;

var arena: heap.ArenaAllocator = undefined;

fn help(writer: anytype, appname: []const u8) !noreturn {
    try writer.print("Usage: {s} [ARG]\n", .{appname});
    arena.deinit();
    process.exit(1);
}

pub fn main() !void {
    var stdout_file = fs.File.stdout().writer(&.{});
    const stdout = &stdout_file.interface;
    var stderr_file = fs.File.stderr().writer(&.{});
    const stderr = &stderr_file.interface;

    arena = heap.ArenaAllocator.init(heap.page_allocator);
    defer arena.deinit();
    const allocator = arena.allocator();

    const args = try process.argsAlloc(allocator);

    if (args.len != 2) {
        try help(stderr, args[0]);
    }

    if (mem.eql(u8, args[1], "--help") or mem.eql(u8, args[1], "-h")) {
        try help(stdout, args[0]);
    }
}