feat: add experimental cli

um_cli/src/main.rs

@@ -0,0 +1,44 @@
+use crate::cmd::Commands;
+use anyhow::Result;
+use clap::Parser;
+use std::process::exit;
+use std::time::Instant;
+
+mod cmd;
+
+#[derive(Parser)]
+#[command(name = "um_cli")]
+#[command(version = "0.1")]
+#[command(about = "um_cli (rust ver.)", long_about = None)]
+struct Cli {
+    #[clap(subcommand)]
+    command: Option<Commands>,
+
+    /// Time command
+    #[clap(long, short, action=clap::ArgAction::SetTrue)]
+    time: Option<bool>,
+}
+
+fn run_command(cli: &Cli) -> Result<i32> {
+    match &cli.command {
+        Some(Commands::QMCv1(cmd)) => cmd.run(),
+        None => {
+            // https://github.com/clap-rs/clap/issues/3857#issuecomment-1161796261
+            todo!("implement a sensible default command, similar to um/cli");
+        }
+    }
+}
+
+fn main() {
+    let cli = Cli::parse();
+    let start = Instant::now();
+    let code = run_command(&cli).unwrap_or_else(|err| {
+        eprintln!("failed to run command: {}", err);
+        -1
+    });
+    let duration = start.elapsed();
+    if let Some(true) = cli.time {
+        eprintln!("time: {:?}", duration);
+    };
+    exit(code);
+}