chore(vendor): add anyhow crate

third_party/crates/clap-4.6.7/examples/pacman.rs

@@ -0,0 +1,158 @@
+use clap::{Arg, ArgAction, Command};
+
+fn cli() -> Command {
+    Command::new("pacman")
+        .about("package manager utility")
+        .version("5.2.1")
+        .subcommand_required(true)
+        .arg_required_else_help(true)
+        // Query subcommand
+        //
+        // Only a few of its arguments are implemented below.
+        .subcommand(
+            Command::new("query")
+                .short_flag('Q')
+                .long_flag("query")
+                .about("Query the package database.")
+                .arg(
+                    Arg::new("search")
+                        .short('s')
+                        .long("search")
+                        .help("search locally installed packages for matching strings")
+                        .conflicts_with("info")
+                        .action(ArgAction::Set)
+                        .num_args(1..),
+                )
+                .arg(
+                    Arg::new("info")
+                        .long("info")
+                        .short('i')
+                        .conflicts_with("search")
+                        .help("view package information")
+                        .action(ArgAction::Set)
+                        .num_args(1..),
+                ),
+        )
+        // Sync subcommand
+        //
+        // Only a few of its arguments are implemented below.
+        .subcommand(
+            Command::new("sync")
+                .short_flag('S')
+                .long_flag("sync")
+                .about("Synchronize packages.")
+                .arg(
+                    Arg::new("search")
+                        .short('s')
+                        .long("search")
+                        .conflicts_with("info")
+                        .action(ArgAction::Set)
+                        .num_args(1..)
+                        .help("search remote repositories for matching strings"),
+                )
+                .arg(
+                    Arg::new("info")
+                        .long("info")
+                        .conflicts_with("search")
+                        .short('i')
+                        .action(ArgAction::SetTrue)
+                        .help("view package information"),
+                )
+                .arg(
+                    Arg::new("package")
+                        .help("packages")
+                        .required_unless_present("search")
+                        .action(ArgAction::Set)
+                        .num_args(1..),
+                ),
+        )
+}
+
+fn main() {
+    let matches = cli().get_matches();
+
+    match matches.subcommand() {
+        Some(("sync", sync_matches)) => {
+            if sync_matches.contains_id("search") {
+                let packages: Vec<_> = sync_matches
+                    .get_many::<String>("search")
+                    .expect("contains_id")
+                    .map(|s| s.as_str())
+                    .collect();
+                let values = packages.join(", ");
+                println!("Searching for {values}...");
+                return;
+            }
+
+            let packages: Vec<_> = sync_matches
+                .get_many::<String>("package")
+                .expect("is present")
+                .map(|s| s.as_str())
+                .collect();
+            let values = packages.join(", ");
+
+            if sync_matches.get_flag("info") {
+                println!("Retrieving info for {values}...");
+            } else {
+                println!("Installing {values}...");
+            }
+        }
+        Some(("query", query_matches)) => {
+            if let Some(packages) = query_matches.get_many::<String>("info") {
+                let comma_sep = packages.map(|s| s.as_str()).collect::<Vec<_>>().join(", ");
+                println!("Retrieving info for {comma_sep}...");
+            } else if let Some(queries) = query_matches.get_many::<String>("search") {
+                let comma_sep = queries.map(|s| s.as_str()).collect::<Vec<_>>().join(", ");
+                println!("Searching Locally for {comma_sep}...");
+            } else {
+                println!("Displaying all locally installed packages...");
+            }
+        }
+        _ => unreachable!(), // If all subcommands are defined above, anything else is unreachable
+    }
+}
+
+#[cfg(all(test, feature = "help", feature = "usage"))]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn help_output_is_stable() {
+        snapbox::assert_data_eq!(
+            render_reference(cli()),
+            snapbox::file!["snapshots/pacman.txt"].raw()
+        );
+    }
+
+    fn render_reference(mut command: Command) -> String {
+        command = command.term_width(0);
+        command.build();
+
+        let mut buffer = String::new();
+        write_help(&mut buffer, &mut command, String::new());
+
+        buffer
+    }
+
+    fn write_help(buffer: &mut String, cmd: &mut Command, mut path: String) {
+        let header = if path.is_empty() { "#" } else { "##" };
+        path.push(' ');
+        path.push_str(cmd.get_name());
+
+        buffer.push_str(header);
+        buffer.push_str(&path);
+        buffer.push_str("\n\n");
+        buffer.push_str(&cmd.render_long_help().to_string());
+
+        let has_generated_help = !cmd.is_disable_help_subcommand_set();
+        for subcommand in cmd.get_subcommands_mut() {
+            // Generated `help` nodes proxy other commands.
+            if has_generated_help && subcommand.get_name() == "help" {
+                continue;
+            }
+
+            buffer.push('\n');
+            write_help(buffer, subcommand, path.clone());
+        }
+    }
+}