zeta eval: --repeat flag (#42569)

Adds a `--repeat` flag to the zeta eval that runs each example as many
times as specified. Also makes the output nicer in a few ways.

Release Notes:

- N/A

---------

Co-authored-by: Ben Kunkle <ben@zed.dev>
Co-authored-by: Michael <michael@zed.dev>

crates/zeta_cli/src/main.rs

@@ -35,8 +35,10 @@ use crate::util::{open_buffer, open_buffer_with_language_server};
 #[derive(Parser, Debug)]
 #[command(name = "zeta")]
 struct ZetaCliArgs {
+    #[arg(long, default_value_t = false)]
+    printenv: bool,
     #[command(subcommand)]
-    command: Command,
+    command: Option<Command>,
 }
 
 #[derive(Subcommand, Debug)]
@@ -413,14 +415,22 @@ fn main() {
         let app_state = Arc::new(headless::init(cx));
         cx.spawn(async move |cx| {
             match args.command {
-                Command::Zeta1 {
+                None => {
+                    if args.printenv {
+                        ::util::shell_env::print_env();
+                        return;
+                    } else {
+                        panic!("Expected a command");
+                    }
+                }
+                Some(Command::Zeta1 {
                     command: Zeta1Command::Context { context_args },
-                } => {
+                }) => {
                     let context = zeta1_context(context_args, &app_state, cx).await.unwrap();
                     let result = serde_json::to_string_pretty(&context.body).unwrap();
                     println!("{}", result);
                 }
-                Command::Zeta2 { command } => match command {
+                Some(Command::Zeta2 { command }) => match command {
                     Zeta2Command::Predict(arguments) => {
                         run_zeta2_predict(arguments, &app_state, cx).await;
                     }
@@ -464,14 +474,16 @@ fn main() {
                         println!("{}", result.unwrap());
                     }
                 },
-                Command::ConvertExample {
+                Some(Command::ConvertExample {
                     path,
                     output_format,
-                } => {
+                }) => {
                     let example = NamedExample::load(path).unwrap();
                     example.write(output_format, io::stdout()).unwrap();
                 }
-                Command::Clean => std::fs::remove_dir_all(&*crate::paths::TARGET_ZETA_DIR).unwrap(),
+                Some(Command::Clean) => {
+                    std::fs::remove_dir_all(&*crate::paths::TARGET_ZETA_DIR).unwrap()
+                }
             };
 
             let _ = cx.update(|cx| cx.quit());