[][src]Function rust_lisp::utils::require_int_parameter

pub fn require_int_parameter(
    func_name: &str,
    args: &Vec<Value>,
    index: usize
) -> Result<i32, RuntimeError>

Given a Value assumed to be a Value::List(), grab the item at index, assumed to be a Value::Int(), and return its inner i32. Err if any part of this fails.