use std::env; use std::fs; use std::io; use std::io::Write; use std::process; mod errors; mod interpreter; mod parser; mod scanner; fn main() { let mut args = env::args(); if args.len() > 2 { println!("Usage: rlox [script]"); process::exit(1); } else if let Some(file) = args.nth(1) { run_file(&file); } else { run_prompt(); } } // Run Lox code from a file and print results to stdout fn run_file(file: &str) { let contents = fs::read_to_string(file).expect("failed to read the input file"); run(&contents); } // Evaluate Lox code interactively in a shitty REPL. fn run_prompt() { let mut line = String::new(); loop { print!("> "); io::stdout().flush().unwrap(); io::stdin() .read_line(&mut line) .expect("failed to read user input"); run(&line); line.clear(); } } fn run(code: &str) { let chars: Vec<char> = code.chars().collect(); let mut lox = interpreter::Interpreter::create(); match scanner::scan(&chars) { Ok(tokens) => match parser::parse(tokens) { Ok(program) => { println!("Program:\n{:?}", program); if let Err(err) = lox.interpret(&program) { println!("Error in program: {:?}", err); } } Err(errors) => report_errors(errors), }, Err(errors) => report_errors(errors), } } fn report_errors(errors: Vec<errors::Error>) { for error in errors { errors::report(&error); } }