object/
builtins.rs

1use crate::{BuiltinFunc, Object};
2use std::rc::Rc;
3
4lazy_static! {
5    pub static ref BuiltIns: Vec<(&'static str, BuiltinFunc)> = vec![
6        ("len", len),
7        ("puts", puts),
8        ("first", first),
9        ("last", last),
10        ("rest", rest),
11        ("push", push),
12        ("print", puts)
13    ];
14}
15
16// a failed try
17// rust sucks: https://stackoverflow.com/a/27896014/1713757
18// pub static BUILTINS: HashMap<String, BuiltinFunc> = vec![(String::from("len"), len as BuiltinFunc) ]
19//     .into_iter()
20//     .collect();
21
22pub fn len(args: Vec<Rc<Object>>) -> Rc<Object> {
23    if args.len() != 1 {
24        return Rc::from(Object::Error(format!(
25            "builtin len expected 1 argument, got {}",
26            args.len()
27        )));
28    }
29    Rc::from(match &*args[0] {
30        Object::String(s) => Object::Integer(s.len() as i64),
31        Object::Array(a) => Object::Integer(a.len() as i64),
32        o => Object::Error(format!("builtin len not supported for for type {}", o)),
33    })
34}
35
36pub fn puts(args: Vec<Rc<Object>>) -> Rc<Object> {
37    args.iter().for_each(|obj| println!("{}", obj));
38    Rc::from(Object::Null)
39}
40
41pub fn first(args: Vec<Rc<Object>>) -> Rc<Object> {
42    match &*args[0] {
43        Object::Array(s) => match s.first() {
44            Some(obj) => Rc::clone(obj),
45            None => Rc::new(Object::Null),
46        },
47        o => Rc::new(Object::Error(format!("builtin first not supported for for type {}", o))),
48    }
49}
50
51pub fn last(args: Vec<Rc<Object>>) -> Rc<Object> {
52    match &*args[0] {
53        Object::Array(s) => match s.last() {
54            Some(obj) => Rc::clone(obj),
55            None => Rc::new(Object::Null),
56        },
57        o => Rc::new(Object::Error(format!("builtin last not supported for for type {}", o))),
58    }
59}
60
61pub fn rest(args: Vec<Rc<Object>>) -> Rc<Object> {
62    match &*args[0] {
63        Object::Array(s) => {
64            let len = s.len();
65            if len > 0 {
66                let new_array = s[1..len].to_vec();
67                return Rc::new(Object::Array(new_array));
68            }
69            return Rc::new(Object::Null);
70        }
71        o => Rc::new(Object::Error(format!("builtin rest not supported for for type {}", o))),
72    }
73}
74
75pub fn push(args: Vec<Rc<Object>>) -> Rc<Object> {
76    let array = args.first().unwrap();
77    let obj = Rc::clone(args.last().unwrap());
78    match &**array {
79        Object::Array(s) => {
80            let mut new_array = s.clone();
81            new_array.push(obj);
82            return Rc::new(Object::Array(new_array));
83        }
84        o => Rc::new(Object::Error(format!("builtin push not supported for for type {}", o))),
85    }
86}
object/builtins.rs

object/
builtins.rs
