add command line args

src/main.zig

@@ -1,4 +1,6 @@
 const std = @import("std");
+const config = @import("config");
+const clap = @import("clap");
 const wlr = @import("wlroots");
 
 const Server = @import("Server.zig");
@@ -10,14 +12,62 @@ pub var server: Server = undefined;
 pub var lua: Lua = undefined;
 pub var env_map: std.process.EnvMap = undefined;
 
-pub fn main() !void {
-  wlr.log.init(.err, null);
+const usage =
+    \\Usage: mez [options]
+    \\
+    \\Options:
+++ "\n" ++ args ++ "\n";
+const args =
+    \\   -u <path>            Use this config
+    \\   -c <command>         Runs this command at startup
+    \\   -v, --version        Print the version and exit
+    \\   -h, --help           Print this help and exit
+    \\
+    \\   --clean              "Factory defaults" (skip user config)
+;
 
+pub fn main() !void {
+  const params = comptime clap.parseParamsComptime(args);
+  var diag = clap.Diagnostic{};
+  const parsers = comptime .{
+    .path = clap.parsers.string,
+    .command = clap.parsers.string,
+  };
+  var res = clap.parse(clap.Help, &params, parsers, .{
+    .diagnostic = &diag,
+    .allocator = gpa,
+  }) catch |err| {
+    try diag.reportToFile(.stderr(), err);
+    return err;
+  };
+  defer res.deinit();
+
+  if (res.args.help == 1) {
+    try @constCast(&std.fs.File.stdout().writer(&[_]u8{}).interface).writeAll(usage);
+    std.process.exit(0);
+  }
+  if (res.args.version == 1) {
+    try @constCast(&std.fs.File.stdout().writer(&[_]u8{}).interface).writeAll(config.version);
+    std.process.exit(0);
+  }
+
+  var lua_config: Lua.Config = .{ .enabled = true, .str = null };
+  if (res.args.u != null and res.args.clean == 1) {
+    std.debug.panic("You cannot set both -u and --clean", .{});
+  } else if (res.args.u != null) {
+    // this is freed in lua/lua.zig
+    const path = try std.fs.cwd().realpathAlloc(gpa, res.args.u.?);
+    lua_config.str = path;
+  } else if (res.args.clean == 1) {
+    lua_config.enabled = false;
+  }
+
+  wlr.log.init(.err, null);
   std.log.info("Starting mezzaluna", .{});
 
   server.init();
   defer server.deinit();
-  try lua.init();
+  try lua.init(lua_config);
 
   var buf: [11]u8 = undefined;
   const socket = try server.wl_server.addSocketAuto(&buf);
@@ -25,8 +75,7 @@ pub fn main() !void {
   env_map = try std.process.getEnvMap(gpa);
   try env_map.put("WAYLAND_DISPLAY", socket);
 
-  if (std.os.argv.len >= 2) {
-    const cmd = std.mem.span(std.os.argv[1]);
+  if (res.args.c) |cmd| {
     var child = std.process.Child.init(&[_][]const u8{ "/bin/sh", "-c", cmd }, gpa);
     child.env_map = &env_map;
     try child.spawn();