ksl 0.1.5

KSL core library and interpreter
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50

use crate::{Environment, eval::apply::eval_apply, value::Value};

pub(crate) fn builtin(args: &[Value], env: &Environment) -> Option<(Value, Environment)> {
    if let [obj, key, val] = &args[..] {
        match (
            eval_apply(obj, env),
            eval_apply(key, env),
            eval_apply(val, env),
        ) {
            (
                Some((Value::Object(type_name, mut dict), _)),
                Some((Value::String(k), _)),
                Some((e, new_env)),
            ) => {
                let _ = dict.insert(k, e);
                Some((Value::Object(type_name, dict), new_env))
            }
            (Some((e1, _)), Some((e2, _)), Some((e3, _))) => {
                eprintln!(
                    concat!(
                        "Error[ksl::builtin::let]: ",
                        "Only accepts an object, a string of key and a value as arguments, ",
                        "but {:?} were passed."
                    ),
                    (e1, e2, e3)
                );
                None
            }
            _ => {
                eprintln!(
                    concat!(
                        "Error[ksl::builtin::set]: ",
                        "Cannot evaluate expression {:?}."
                    ),
                    (obj, key, val)
                );
                None
            }
        }
    } else {
        eprintln!(
            concat!(
                "Error[ksl::builtin::set]: ",
                "Only accepts 3 arguments, but {} were passed."
            ),
            args.len()
        );
        None
    }
}