93 lines
2.5 KiB
Rust
93 lines
2.5 KiB
Rust
use std::io::Write;
|
|
|
|
use clap::Command;
|
|
|
|
fn main() -> Result<(), String> {
|
|
loop {
|
|
let line = readline()?;
|
|
let line = line.trim();
|
|
if line.is_empty() {
|
|
continue;
|
|
}
|
|
|
|
match respond(line) {
|
|
Ok(quit) => {
|
|
if quit {
|
|
break;
|
|
}
|
|
}
|
|
Err(err) => {
|
|
write!(std::io::stdout(), "{err}").map_err(|e| e.to_string())?;
|
|
std::io::stdout().flush().map_err(|e| e.to_string())?;
|
|
}
|
|
}
|
|
}
|
|
|
|
Ok(())
|
|
}
|
|
|
|
fn respond(line: &str) -> Result<bool, String> {
|
|
let args = shlex::split(line).ok_or("error: Invalid quoting")?;
|
|
let matches = cli()
|
|
.try_get_matches_from(args)
|
|
.map_err(|e| e.to_string())?;
|
|
match matches.subcommand() {
|
|
Some(("ping", _matches)) => {
|
|
write!(std::io::stdout(), "Pong").map_err(|e| e.to_string())?;
|
|
std::io::stdout().flush().map_err(|e| e.to_string())?;
|
|
}
|
|
Some(("quit", _matches)) => {
|
|
write!(std::io::stdout(), "Exiting ...").map_err(|e| e.to_string())?;
|
|
std::io::stdout().flush().map_err(|e| e.to_string())?;
|
|
return Ok(true);
|
|
}
|
|
Some((name, _matches)) => unimplemented!("{name}"),
|
|
None => unreachable!("subcommand required"),
|
|
}
|
|
|
|
Ok(false)
|
|
}
|
|
|
|
fn cli() -> Command {
|
|
// strip out usage
|
|
const PARSER_TEMPLATE: &str = "\
|
|
{all-args}
|
|
";
|
|
// strip out name/version
|
|
const APPLET_TEMPLATE: &str = "\
|
|
{about-with-newline}\n\
|
|
{usage-heading}\n {usage}\n\
|
|
\n\
|
|
{all-args}{after-help}\
|
|
";
|
|
|
|
Command::new("repl")
|
|
.multicall(true)
|
|
.arg_required_else_help(true)
|
|
.subcommand_required(true)
|
|
.subcommand_value_name("APPLET")
|
|
.subcommand_help_heading("APPLETS")
|
|
.help_template(PARSER_TEMPLATE)
|
|
.subcommand(
|
|
Command::new("ping")
|
|
.about("Get a response")
|
|
.help_template(APPLET_TEMPLATE),
|
|
)
|
|
.subcommand(
|
|
Command::new("quit")
|
|
.alias("exit")
|
|
.about("Quit the REPL")
|
|
.help_template(APPLET_TEMPLATE),
|
|
)
|
|
}
|
|
|
|
fn readline() -> Result<String, String> {
|
|
write!(std::io::stdout(), "$ ").map_err(|e| e.to_string())?;
|
|
std::io::stdout().flush().map_err(|e| e.to_string())?;
|
|
let mut buffer = String::new();
|
|
std::io::stdin()
|
|
.read_line(&mut buffer)
|
|
.map_err(|e| e.to_string())?;
|
|
Ok(buffer)
|
|
}
|