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use melisp::parse::parsetree::parse_to_ast;
use melisp::sexp::{SExp::*, SLeaf::Nil};
use std::{io, io::Write};
fn main() {
match repl() {
Ok(()) => println!("bye :)"),
Err(e) => {
println!("Error: {}", e);
main();
},
}
}
fn repl() -> Result<(), String> {
let stdin = io::stdin();
let mut input = String::new();
let mut stdout = io::stdout();
print!("> ");
match stdout.flush() {
Ok(_) => (),
Err(_) => println!("Enter s-expression:"),
};
let mut success = stdin.read_line(&mut input);
while success.is_ok() && input != "exit\n" {
if let Ok(0) = success {
print!("\n");
break;
}
let expression = match parse_to_ast(&input) {
Ok(SCons(a, b)) if *b == Atom(Nil) => Ok(*a),
t => t
}?;
let ty = expression.type_check().map_err(|e| e.to_string())?;
let result = expression.multistep()?;
println!("{} : {}", result, ty);
print!("> ");
match stdout.flush() {
Ok(_) => (),
Err(_) => println!("Enter s-expression:"),
};
input.clear();
success = stdin.read_line(&mut input);
}
match success {
Ok(_) => Ok(()),
Err(e) => Err(format!("read error: {e}")),
}
}
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