object/
builtins.rs

1use crate::{BuiltinFunc, Object};
2use std::rc::Rc;
3
4#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
5pub enum BuiltinId {
6    Len,
7    Puts,
8    First,
9    Last,
10    Rest,
11    Push,
12}
13
14#[derive(Clone, Copy)]
15pub struct BuiltinDefinition {
16    pub name: &'static str,
17    pub id: BuiltinId,
18    pub function: BuiltinFunc,
19}
20
21lazy_static! {
22    pub static ref BuiltIns: Vec<BuiltinDefinition> = vec![
23        BuiltinDefinition {
24            name: "len",
25            id: BuiltinId::Len,
26            function: len
27        },
28        BuiltinDefinition {
29            name: "puts",
30            id: BuiltinId::Puts,
31            function: puts
32        },
33        BuiltinDefinition {
34            name: "first",
35            id: BuiltinId::First,
36            function: first
37        },
38        BuiltinDefinition {
39            name: "last",
40            id: BuiltinId::Last,
41            function: last
42        },
43        BuiltinDefinition {
44            name: "rest",
45            id: BuiltinId::Rest,
46            function: rest
47        },
48        BuiltinDefinition {
49            name: "push",
50            id: BuiltinId::Push,
51            function: push
52        },
53        BuiltinDefinition {
54            name: "print",
55            id: BuiltinId::Puts,
56            function: puts
57        },
58    ];
59}
60
61// a failed try
62// rust sucks: https://stackoverflow.com/a/27896014/1713757
63// pub static BUILTINS: HashMap<String, BuiltinFunc> = vec![(String::from("len"), len as BuiltinFunc) ]
64//     .into_iter()
65//     .collect();
66
67pub fn len(args: Vec<Rc<Object>>) -> Rc<Object> {
68    if args.len() != 1 {
69        return Rc::from(Object::Error(format!(
70            "builtin len expected 1 argument, got {}",
71            args.len()
72        )));
73    }
74    Rc::from(match &*args[0] {
75        Object::String(s) => Object::Integer(s.len() as i64),
76        Object::Array(a) => Object::Integer(a.len() as i64),
77        o => Object::Error(format!("builtin len not supported for for type {}", o)),
78    })
79}
80
81pub fn puts(args: Vec<Rc<Object>>) -> Rc<Object> {
82    args.iter().for_each(|obj| println!("{}", obj));
83    Rc::from(Object::Null)
84}
85
86pub fn first(args: Vec<Rc<Object>>) -> Rc<Object> {
87    match &*args[0] {
88        Object::Array(s) => match s.first() {
89            Some(obj) => Rc::clone(obj),
90            None => Rc::new(Object::Null),
91        },
92        o => Rc::new(Object::Error(format!("builtin first not supported for for type {}", o))),
93    }
94}
95
96pub fn last(args: Vec<Rc<Object>>) -> Rc<Object> {
97    match &*args[0] {
98        Object::Array(s) => match s.last() {
99            Some(obj) => Rc::clone(obj),
100            None => Rc::new(Object::Null),
101        },
102        o => Rc::new(Object::Error(format!("builtin last not supported for for type {}", o))),
103    }
104}
105
106pub fn rest(args: Vec<Rc<Object>>) -> Rc<Object> {
107    match &*args[0] {
108        Object::Array(s) => {
109            let len = s.len();
110            if len > 0 {
111                let new_array = s[1..len].to_vec();
112                return Rc::new(Object::Array(new_array));
113            }
114            return Rc::new(Object::Null);
115        }
116        o => Rc::new(Object::Error(format!("builtin rest not supported for for type {}", o))),
117    }
118}
119
120pub fn push(args: Vec<Rc<Object>>) -> Rc<Object> {
121    let array = args.first().unwrap();
122    let obj = Rc::clone(args.last().unwrap());
123    match &**array {
124        Object::Array(s) => {
125            let mut new_array = s.clone();
126            new_array.push(obj);
127            return Rc::new(Object::Array(new_array));
128        }
129        o => Rc::new(Object::Error(format!("builtin push not supported for for type {}", o))),
130    }
131}
object/builtins.rs

object/
builtins.rs
