docs(derive): Clarify subcommand arg syntax

Cargo.toml

@@ -309,6 +309,11 @@ name = "03_04_subcommands_derive"
 path = "examples/tutorial_derive/03_04_subcommands.rs"
 required-features = ["derive"]
 
+[[example]]
+name = "03_04_subcommands_alt_derive"
+path = "examples/tutorial_derive/03_04_subcommands_alt.rs"
+required-features = ["derive"]
+
 [[example]]
 name = "03_05_default_values_derive"
 path = "examples/tutorial_derive/03_05_default_values.rs"

examples/tutorial_derive/03_04_subcommands_alt.rs

@@ -0,0 +1,32 @@
+use clap::{Parser, Subcommand, Args};
+
+#[derive(Parser)]
+#[clap(author, version, about, long_about = None)]
+#[clap(propagate_version = true)]
+struct Cli {
+    #[clap(subcommand)]
+    command: Commands,
+}
+
+#[derive(Subcommand)]
+enum Commands {
+    /// Adds files to myapp
+    Add(Add),
+}
+
+#[derive(Args)]
+struct Add {
+    name: Option<String>
+}
+
+fn main() {
+    let cli = Cli::parse();
+
+    // You can check for the existence of subcommands, and if found use their
+    // matches just as you would the top level cmd
+    match &cli.command {
+        Commands::Add { name } => {
+            println!("'myapp add' was used, name is: {:?}", name)
+        }
+    }
+}

examples/tutorial_derive/README.md

@@ -306,6 +306,10 @@ $ 03_04_subcommands_derive add bob
 
 ```
 
+Above, we used a struct-variant to define the `add` subcommand.  Alternatively,
+you can
+[use a struct for your subcommand's arguments](03_04_subcommands_alt_derive.rs).
+
 Because we used `command: Commands` instead of `command: Option<Commands>`:
 ```console
 $ 03_04_subcommands_derive