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
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
|
extern crate mal;
use std::collections::HashMap;
use mal::types::{MalVal, MalRet, MalError, err_str};
use mal::types::{symbol, _nil, list, vector, hash_map, malfunc};
use mal::types::MalError::{ErrString, ErrMalVal};
use mal::types::MalType::{Nil, False, Sym, List, Vector, Hash_Map, Func, MalFunc};
use mal::{readline, reader, core};
use mal::env::{env_set, env_get, env_new, env_bind, Env};
// read
fn read(str: String) -> MalRet {
reader::read_str(str)
}
// eval
fn eval_ast(ast: MalVal, env: Env) -> MalRet {
match *ast {
Sym(_) => env_get(&env, &ast),
List(ref a,_) | Vector(ref a,_) => {
let mut ast_vec : Vec<MalVal> = vec![];
for mv in a.iter() {
let mv2 = mv.clone();
ast_vec.push(try!(eval(mv2, env.clone())));
}
Ok(match *ast { List(_,_) => list(ast_vec),
_ => vector(ast_vec) })
}
Hash_Map(ref hm,_) => {
let mut new_hm: HashMap<String,MalVal> = HashMap::new();
for (key, value) in hm.iter() {
new_hm.insert(key.to_string(),
try!(eval(value.clone(), env.clone())));
}
Ok(hash_map(new_hm))
}
_ => Ok(ast.clone()),
}
}
fn eval(mut ast: MalVal, mut env: Env) -> MalRet {
'tco: loop {
//println!("eval: {}, {}", ast, env.borrow());
//println!("eval: {}", ast);
match *ast {
List(_,_) => (), // continue
_ => return eval_ast(ast, env),
}
// apply list
match *ast {
List(_,_) => (), // continue
_ => return Ok(ast),
}
let tmp = ast;
let (args, a0sym) = match *tmp {
List(ref args,_) => {
if args.len() == 0 {
return Ok(tmp.clone());
}
let ref a0 = *args[0];
match *a0 {
Sym(ref a0sym) => (args, &a0sym[..]),
_ => (args, "__<fn*>__"),
}
},
_ => return err_str("Expected list"),
};
match a0sym {
"def!" => {
let a1 = (*args)[1].clone();
let a2 = (*args)[2].clone();
let r = try!(eval(a2, env.clone()));
match *a1 {
Sym(_) => {
env_set(&env.clone(), a1, r.clone());
return Ok(r);
},
_ => return err_str("def! of non-symbol"),
}
},
"let*" => {
let let_env = env_new(Some(env.clone()));
let a1 = (*args)[1].clone();
let a2 = (*args)[2].clone();
match *a1 {
List(ref binds,_) | Vector(ref binds,_) => {
let mut it = binds.iter();
while it.len() >= 2 {
let b = it.next().unwrap();
let exp = it.next().unwrap();
match **b {
Sym(_) => {
let r = try!(eval(exp.clone(), let_env.clone()));
env_set(&let_env, b.clone(), r);
},
_ => return err_str("let* with non-symbol binding"),
}
}
},
_ => return err_str("let* with non-list bindings"),
}
ast = a2;
env = let_env.clone();
continue 'tco;
},
"do" => {
let el = list(args[1..args.len()-1].to_vec());
try!(eval_ast(el, env.clone()));
ast = args[args.len() - 1].clone();
continue 'tco;
},
"if" => {
let a1 = (*args)[1].clone();
let c = try!(eval(a1, env.clone()));
match *c {
False | Nil => {
if args.len() >= 4 {
ast = args[3].clone();
continue 'tco;
} else {
return Ok(_nil());
}
},
_ => {
ast = args[2].clone();
continue 'tco;
},
}
},
"fn*" => {
let a1 = args[1].clone();
let a2 = args[2].clone();
return Ok(malfunc(eval, a2, env, a1, _nil()));
},
_ => { // function call
let el = try!(eval_ast(tmp.clone(), env.clone()));
let args = match *el {
List(ref args,_) => args,
_ => return err_str("Invalid apply"),
};
return match *args.clone()[0] {
Func(f,_) => f(args[1..].to_vec()),
MalFunc(ref mf,_) => {
let mfc = mf.clone();
let alst = list(args[1..].to_vec());
let new_env = env_new(Some(mfc.env.clone()));
match env_bind(&new_env, mfc.params, alst) {
Ok(_) => {
ast = mfc.exp;
env = new_env;
continue 'tco;
},
Err(e) => err_str(&e),
}
},
_ => err_str("attempt to call non-function"),
}
},
}
}
}
// print
fn print(exp: MalVal) -> String {
exp.pr_str(true)
}
fn rep(str: &str, env: Env) -> Result<String,MalError> {
let ast = try!(read(str.to_string()));
//println!("read: {}", ast);
let exp = try!(eval(ast, env));
Ok(print(exp))
}
fn main() {
// core.rs: defined using rust
let repl_env = env_new(None);
for (k, v) in core::ns().into_iter() {
env_set(&repl_env, symbol(&k), v);
}
// core.mal: defined using the language itself
let _ = rep("(def! not (fn* (a) (if a false true)))", repl_env.clone());
// repl loop
loop {
let line = readline::mal_readline("user> ");
match line { None => break, _ => () }
match rep(&line.unwrap(), repl_env.clone()) {
Ok(str) => println!("{}", str),
Err(ErrMalVal(_)) => (), // Blank line
Err(ErrString(s)) => println!("Error: {}", s),
}
}
}
|
