use crate::functions::num::to_int;
use crate::types::Error;
use crate::types::Error::*;
pub fn add(args: Vec<String>) -> Result<String, Error> {
if args.len() < 2 {
return Err(InvalidNativeFunctionArgs(String::from("add"), args.len()));
}
args.iter()
.try_fold(0i64, |cur, x| {
cur.checked_add(to_int(x)).ok_or(Error::OutOfRange)
})
.map(|val| val.to_string())
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn wrong_n_arguments() {
assert_eq!(
add(vec![String::from("a")]).err().unwrap(),
InvalidNativeFunctionArgs(String::from("add"), 1)
);
}
#[test]
fn test_add() {
assert_eq!(
String::from("4"),
add(vec![String::from("2"), String::from("2")])
.ok()
.unwrap()
);
assert_eq!(
String::from("6"),
add(vec![
String::from("2"),
String::from("2"),
String::from("2")
])
.ok()
.unwrap()
);
}
}