zig init: allow specifying project path

Author: fel1x-developer

src/main.zig

@@ -4624,10 +4624,11 @@ fn cmdTranslateC(
 }
 
 const usage_init =
-    \\Usage: zig init
+    \\Usage: zig init [path]
     \\
-    \\   Initializes a `zig build` project in the current working
-    \\   directory.
+    \\   Initializes a `zig build` project in the specified
+    \\   path. If path is not provided, initialize in the
+    \\   current working directory.
     \\
     \\Options:
     \\  -s, --strip            Generate files without comments
@@ -4640,6 +4641,8 @@ fn cmdInit(gpa: Allocator, arena: Allocator, args: []const []const u8) !void {
     dev.check(.init_command);
 
     var strip = false;
+    var path_specified = false;
+    var path: []const u8 = "";
     {
         var i: usize = 0;
         while (i < args.len) : (i += 1) {
@@ -4654,7 +4657,12 @@ fn cmdInit(gpa: Allocator, arena: Allocator, args: []const []const u8) !void {
                     fatal("unrecognized parameter: '{s}'", .{arg});
                 }
             } else {
-                fatal("unexpected extra parameter: '{s}'", .{arg});
+                if (path_specified) {
+                    fatal("more than one path specified", .{});
+                }
+                path_specified = true;
+
+                path = arg;
             }
         }
     }
@@ -4666,6 +4674,19 @@ fn cmdInit(gpa: Allocator, arena: Allocator, args: []const []const u8) !void {
     const cwd_basename = fs.path.basename(cwd_path);
     const sanitized_root_name = try sanitizeExampleName(arena, cwd_basename);
 
+    var out_dir = fs.cwd();
+    if (path_specified) {
+        fs.cwd().makePath(path) catch |e|
+            switch (e) {
+                error.PathAlreadyExists => return,
+                error.NotDir => {
+                    fatal("specified path contains non-directory", .{});
+                },
+                else => return e,
+            };
+        out_dir = try fs.cwd().openDir(path, .{});
+    }
+
     const s = fs.path.sep_str;
     const template_paths = [_][]const u8{
         Package.build_zig_basename,
@@ -4678,7 +4699,7 @@ fn cmdInit(gpa: Allocator, arena: Allocator, args: []const []const u8) !void {
     const fingerprint: Package.Fingerprint = .generate(sanitized_root_name);
 
     for (template_paths) |template_path| {
-        if (templates.write(arena, fs.cwd(), sanitized_root_name, template_path, fingerprint)) |_| {
+        if (templates.write(arena, out_dir, sanitized_root_name, template_path, fingerprint)) |_| {
             std.log.info("created {s}", .{template_path});
             ok_count += 1;
         } else |err| switch (err) {