rhai/examples/rhai_runner.rs

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use rhai::{Engine, EvalAltResult};
use std::{env, fs::File, io::Read, iter, process::exit};
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fn padding(pad: &str, len: usize) -> String {
iter::repeat(pad).take(len).collect::<String>()
}
fn eprint_error(input: &str, err: EvalAltResult) {
fn eprint_line(lines: &Vec<&str>, line: usize, pos: usize, err: &str) {
let line_no = format!("{}: ", line);
let pos_text = format!(" (line {}, position {})", line, pos);
eprintln!("{}{}", line_no, lines[line - 1]);
eprintln!(
"{}^ {}",
padding(" ", line_no.len() + pos - 1),
err.replace(&pos_text, "")
);
eprintln!("");
}
let lines: Vec<_> = input.split("\n").collect();
// Print error
match err.position() {
p if p.is_eof() => {
// EOF
let line = lines.len() - 1;
let pos = lines[line - 1].len();
eprint_line(&lines, line, pos, &err.to_string());
}
p if p.is_none() => {
// No position
eprintln!("{}", err);
}
p => {
// Specific position
eprint_line(
&lines,
p.line().unwrap(),
p.position().unwrap(),
&err.to_string(),
)
}
}
}
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fn main() {
for filename in env::args().skip(1) {
let mut engine = Engine::new();
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let mut f = match File::open(&filename) {
Err(err) => {
eprintln!("Error reading script file: {}\n{}", filename, err);
exit(1);
}
Ok(f) => f,
};
let mut contents = String::new();
match f.read_to_string(&mut contents) {
Err(err) => {
eprintln!("Error reading script file: {}\n{}", filename, err);
exit(1);
}
_ => (),
}
if let Err(err) = engine.consume(&contents) {
eprintln!("{}", padding("=", filename.len()));
eprintln!("{}", filename);
eprintln!("{}", padding("=", filename.len()));
eprintln!("");
eprint_error(&contents, err);
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}
}
}