1 use std::io::Write;
2
3 use clap::{Parser, Subcommand};
4
main() -> Result<(), String>5 fn main() -> Result<(), String> {
6 loop {
7 let line = readline()?;
8 let line = line.trim();
9 if line.is_empty() {
10 continue;
11 }
12
13 match respond(line) {
14 Ok(quit) => {
15 if quit {
16 break;
17 }
18 }
19 Err(err) => {
20 write!(std::io::stdout(), "{err}").map_err(|e| e.to_string())?;
21 std::io::stdout().flush().map_err(|e| e.to_string())?;
22 }
23 }
24 }
25
26 Ok(())
27 }
28
respond(line: &str) -> Result<bool, String>29 fn respond(line: &str) -> Result<bool, String> {
30 let args = shlex::split(line).ok_or("error: Invalid quoting")?;
31 let cli = Cli::try_parse_from(args).map_err(|e| e.to_string())?;
32 match cli.command {
33 Commands::Ping => {
34 write!(std::io::stdout(), "Pong").map_err(|e| e.to_string())?;
35 std::io::stdout().flush().map_err(|e| e.to_string())?;
36 }
37 Commands::Exit => {
38 write!(std::io::stdout(), "Exiting ...").map_err(|e| e.to_string())?;
39 std::io::stdout().flush().map_err(|e| e.to_string())?;
40 return Ok(true);
41 }
42 }
43 Ok(false)
44 }
45
46 #[derive(Debug, Parser)]
47 #[command(multicall = true)]
48 struct Cli {
49 #[command(subcommand)]
50 command: Commands,
51 }
52
53 #[derive(Debug, Subcommand)]
54 enum Commands {
55 Ping,
56 Exit,
57 }
58
readline() -> Result<String, String>59 fn readline() -> Result<String, String> {
60 write!(std::io::stdout(), "$ ").map_err(|e| e.to_string())?;
61 std::io::stdout().flush().map_err(|e| e.to_string())?;
62 let mut buffer = String::new();
63 std::io::stdin()
64 .read_line(&mut buffer)
65 .map_err(|e| e.to_string())?;
66 Ok(buffer)
67 }
68