chore(vendor): add anyhow crate

third_party/crates/clap-4.6.7/examples/derive_ref/hand_subcommand.rs

@@ -0,0 +1,80 @@
+#![allow(dead_code)]
+use clap::error::{Error, ErrorKind};
+use clap::{ArgMatches, Args as _, Command, FromArgMatches, Parser, Subcommand};
+
+#[derive(Parser, Debug)]
+struct AddArgs {
+    name: Vec<String>,
+}
+#[derive(Parser, Debug)]
+struct RemoveArgs {
+    #[arg(short, long)]
+    force: bool,
+    name: Vec<String>,
+}
+
+#[derive(Debug)]
+enum CliSub {
+    Add(AddArgs),
+    Remove(RemoveArgs),
+}
+
+impl FromArgMatches for CliSub {
+    fn from_arg_matches(matches: &ArgMatches) -> Result<Self, Error> {
+        match matches.subcommand() {
+            Some(("add", args)) => Ok(Self::Add(AddArgs::from_arg_matches(args)?)),
+            Some(("remove", args)) => Ok(Self::Remove(RemoveArgs::from_arg_matches(args)?)),
+            Some((_, _)) => Err(Error::raw(
+                ErrorKind::InvalidSubcommand,
+                "Valid subcommands are `add` and `remove`",
+            )),
+            None => Err(Error::raw(
+                ErrorKind::MissingSubcommand,
+                "Valid subcommands are `add` and `remove`",
+            )),
+        }
+    }
+    fn update_from_arg_matches(&mut self, matches: &ArgMatches) -> Result<(), Error> {
+        match matches.subcommand() {
+            Some(("add", args)) => *self = Self::Add(AddArgs::from_arg_matches(args)?),
+            Some(("remove", args)) => *self = Self::Remove(RemoveArgs::from_arg_matches(args)?),
+            Some((_, _)) => {
+                return Err(Error::raw(
+                    ErrorKind::InvalidSubcommand,
+                    "Valid subcommands are `add` and `remove`",
+                ));
+            }
+            None => (),
+        };
+        Ok(())
+    }
+}
+
+impl Subcommand for CliSub {
+    fn augment_subcommands(cmd: Command) -> Command {
+        cmd.subcommand(AddArgs::augment_args(Command::new("add")))
+            .subcommand(RemoveArgs::augment_args(Command::new("remove")))
+            .subcommand_required(true)
+    }
+    fn augment_subcommands_for_update(cmd: Command) -> Command {
+        cmd.subcommand(AddArgs::augment_args(Command::new("add")))
+            .subcommand(RemoveArgs::augment_args(Command::new("remove")))
+            .subcommand_required(true)
+    }
+    fn has_subcommand(name: &str) -> bool {
+        matches!(name, "add" | "remove")
+    }
+}
+
+#[derive(Parser, Debug)]
+struct Cli {
+    #[arg(short, long)]
+    top_level: bool,
+    #[command(subcommand)]
+    subcommand: CliSub,
+}
+
+fn main() {
+    let args = Cli::parse();
+    println!("{args:#?}");
+}