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#[cfg(test)]
pub mod tests;
pub mod lib;
use rustyline::error::ReadlineError;
use rustyline::Editor;
fn read<T: rustyline::Helper>(rl: &mut Editor<T>) -> Option<String> {
let readline = rl.readline(">> ");
match readline {
Ok(line) => {
rl.add_history_entry(line.as_str());
Some(line)
},
Err(ReadlineError::Interrupted) => {
println!("CTRL-C");
None
},
Err(ReadlineError::Eof) => {
println!("CTRL-D");
None
},
Err(err) => {
println!("Error: {:?}", err);
None
}
}
}
fn means_exit(input: &str) -> bool {
match input {
"exit" | "quit" | ",q" => true,
_ => false
}
}
fn eval(env: &mut lib::eval::Env, input: &str) -> String {
let sexp = match lib::parse::parse(input) {
Ok(x) => x,
Err(f) => return f
};
println!("{:?}", sexp);
let res = lib::eval::eval(&sexp, env);
match res {
Ok(x) => format!("{:?}", x),
Err(f) => f
}
}
fn main() {
let mut env = lib::eval::Env::new();
let hist_file = "history.txt";
// `()` can be used when no completer is required
let mut rl = Editor::<()>::new();
if rl.load_history(hist_file).is_err() {
println!("No previous history.");
}
loop {
let input_line = read(&mut rl);
let line = match input_line {
None => break,
Some(expr) if means_exit(&expr) => break,
Some(expr) => expr
};
println!("{}", eval(&mut env, &line));
}
rl.save_history(hist_file).unwrap();
}
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