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4ef4b17c JM |
1 | use std::rc::Rc; |
2 | //use std::collections::HashMap; | |
3 | use fnv::FnvHashMap; | |
4 | use itertools::Itertools; | |
5 | ||
6 | #[macro_use] | |
7 | extern crate lazy_static; | |
8 | extern crate regex; | |
9 | extern crate itertools; | |
10 | extern crate fnv; | |
11 | ||
12 | extern crate rustyline; | |
13 | use rustyline::error::ReadlineError; | |
14 | use rustyline::Editor; | |
15 | ||
16 | #[macro_use] | |
17 | mod types; | |
18 | use types::{MalVal,MalArgs,MalRet,MalErr,error,format_error}; | |
19 | use types::MalVal::{Nil,Bool,Str,Sym,List,Vector,Hash,Func,MalFunc}; | |
20 | use types::MalErr::{ErrString,ErrMalVal}; | |
21 | mod reader; | |
22 | mod printer; | |
23 | mod env; | |
24 | use env::{Env,env_new,env_bind,env_find,env_get,env_set,env_sets}; | |
25 | #[macro_use] | |
26 | mod core; | |
27 | ||
28 | // read | |
29 | fn read(str: &str) -> MalRet { | |
30 | reader::read_str(str.to_string()) | |
31 | } | |
32 | ||
33 | // eval | |
34 | fn quasiquote(ast: &MalVal) -> MalVal { | |
35 | match ast { | |
36 | List(ref v,_) | Vector(ref v,_) if v.len() > 0 => { | |
37 | let a0 = &v[0]; | |
38 | match a0 { | |
39 | Sym(ref s) if s == "unquote" => v[1].clone(), | |
40 | _ => { | |
41 | match a0 { | |
42 | List(ref v0,_) | Vector(ref v0,_) if v0.len() > 0 => { | |
43 | match v0[0] { | |
44 | Sym(ref s) if s == "splice-unquote" => { | |
45 | list![Sym("concat".to_string()), | |
46 | v0[1].clone(), | |
47 | quasiquote(&list!(v[1..].to_vec()))] | |
48 | }, | |
49 | _ => { | |
50 | list![Sym("cons".to_string()), | |
51 | quasiquote(a0), | |
52 | quasiquote(&list!(v[1..].to_vec()))] | |
53 | }, | |
54 | } | |
55 | }, | |
56 | _ => { | |
57 | list![Sym("cons".to_string()), | |
58 | quasiquote(a0), | |
59 | quasiquote(&list!(v[1..].to_vec()))] | |
60 | } | |
61 | } | |
62 | } | |
63 | } | |
64 | }, | |
65 | _ => list![Sym("quote".to_string()), ast.clone()] | |
66 | } | |
67 | } | |
68 | ||
69 | fn is_macro_call(ast: &MalVal, env: &Env) -> Option<(MalVal,MalArgs)> { | |
70 | match ast { | |
71 | List(v,_) => { | |
72 | match v[0] { | |
73 | Sym(ref s) => { | |
74 | match env_find(env, s) { | |
75 | Some(e) => { | |
76 | match env_get(&e, &v[0]) { | |
77 | Ok(f @ MalFunc{is_macro: true, ..}) => { | |
78 | Some((f, v[1..].to_vec())) | |
79 | }, | |
80 | _ => None, | |
81 | } | |
82 | }, | |
83 | _ => None, | |
84 | } | |
85 | }, | |
86 | _ => None, | |
87 | } | |
88 | }, | |
89 | _ => None, | |
90 | } | |
91 | } | |
92 | ||
93 | fn macroexpand(mut ast: MalVal, env: &Env) -> (bool, MalRet) { | |
94 | let mut was_expanded = false; | |
95 | while let Some((mf, args)) = is_macro_call(&ast, env) { | |
96 | //println!("macroexpand 1: {:?}", ast); | |
97 | ast = match mf.apply(args) { | |
98 | Err(e) => return (false, Err(e)), | |
99 | Ok(a) => a, | |
100 | }; | |
101 | //println!("macroexpand 2: {:?}", ast); | |
102 | was_expanded = true; | |
103 | } | |
104 | ((was_expanded, Ok(ast))) | |
105 | } | |
106 | ||
107 | fn eval_ast(ast: &MalVal, env: &Env) -> MalRet { | |
108 | match ast { | |
109 | Sym(_) => Ok(env_get(&env, &ast)?), | |
110 | List(v,_) => { | |
111 | let mut lst: MalArgs = vec![]; | |
112 | for a in v.iter() { lst.push(eval(a.clone(), env.clone())?) } | |
113 | Ok(list!(lst)) | |
114 | }, | |
115 | Vector(v,_) => { | |
116 | let mut lst: MalArgs = vec![]; | |
117 | for a in v.iter() { lst.push(eval(a.clone(), env.clone())?) } | |
118 | Ok(vector!(lst)) | |
119 | }, | |
120 | Hash(hm,_) => { | |
121 | let mut new_hm: FnvHashMap<String,MalVal> = FnvHashMap::default(); | |
122 | for (k,v) in hm.iter() { | |
123 | new_hm.insert(k.to_string(), eval(v.clone(), env.clone())?); | |
124 | } | |
125 | Ok(Hash(Rc::new(new_hm),Rc::new(Nil))) | |
126 | }, | |
127 | _ => Ok(ast.clone()), | |
128 | } | |
129 | } | |
130 | ||
131 | fn eval(mut ast: MalVal, mut env: Env) -> MalRet { | |
132 | let ret: MalRet; | |
133 | ||
134 | 'tco: loop { | |
135 | ||
136 | ret = match ast.clone() { | |
137 | List(l,_) => { | |
90ca8485 | 138 | if l.len() == 0 { return Ok(ast); } |
4ef4b17c JM |
139 | match macroexpand(ast.clone(), &env) { |
140 | (true, Ok(new_ast)) => { | |
141 | ast = new_ast; | |
142 | continue 'tco; | |
143 | } | |
144 | (_, Err(e)) => return Err(e), | |
145 | _ => (), | |
146 | } | |
147 | ||
148 | if l.len() == 0 { return Ok(ast); } | |
149 | let a0 = &l[0]; | |
150 | match a0 { | |
151 | Sym(ref a0sym) if a0sym == "def!" => { | |
152 | env_set(&env, l[1].clone(), eval(l[2].clone(), env.clone())?) | |
153 | }, | |
154 | Sym(ref a0sym) if a0sym == "let*" => { | |
155 | env = env_new(Some(env.clone())); | |
156 | let (a1, a2) = (l[1].clone(), l[2].clone()); | |
157 | match a1 { | |
158 | List(ref binds,_) | Vector(ref binds,_) => { | |
159 | for (b, e) in binds.iter().tuples() { | |
160 | match b { | |
161 | Sym(_) => { | |
162 | let _ = env_set(&env, b.clone(), | |
163 | eval(e.clone(), env.clone())?); | |
164 | }, | |
165 | _ => { | |
166 | return error("let* with non-Sym binding"); | |
167 | } | |
168 | } | |
169 | } | |
170 | }, | |
171 | _ => { | |
172 | return error("let* with non-List bindings"); | |
173 | } | |
174 | }; | |
175 | ast = a2; | |
176 | continue 'tco; | |
177 | }, | |
178 | Sym(ref a0sym) if a0sym == "quote" => { | |
179 | Ok(l[1].clone()) | |
180 | }, | |
181 | Sym(ref a0sym) if a0sym == "quasiquote" => { | |
182 | ast = quasiquote(&l[1]); | |
183 | continue 'tco; | |
184 | }, | |
185 | Sym(ref a0sym) if a0sym == "defmacro!" => { | |
186 | let (a1, a2) = (l[1].clone(), l[2].clone()); | |
187 | let r = eval(a2, env.clone())?; | |
188 | match r { | |
189 | MalFunc{eval, ast, env, params, ..} => { | |
190 | Ok(env_set(&env, a1.clone(), | |
191 | MalFunc{eval: eval, ast: ast.clone(), env: env.clone(), | |
192 | params: params.clone(), is_macro: true, | |
193 | meta: Rc::new(Nil)})?) | |
194 | }, | |
195 | _ => error("set_macro on non-function"), | |
196 | } | |
197 | }, | |
198 | Sym(ref a0sym) if a0sym == "macroexpand" => { | |
199 | match macroexpand(l[1].clone(), &env) { | |
200 | (_, Ok(new_ast)) => Ok(new_ast), | |
201 | (_, e) => return e, | |
202 | } | |
203 | }, | |
204 | Sym(ref a0sym) if a0sym == "try*" => { | |
205 | match eval(l[1].clone(), env.clone()) { | |
206 | Err(ref e) if l.len() >= 3 => { | |
207 | let exc = match e { | |
208 | ErrMalVal(mv) => mv.clone(), | |
209 | ErrString(s) => Str(s.to_string()), | |
210 | }; | |
211 | match l[2].clone() { | |
212 | List(c,_) => { | |
213 | let catch_env = env_bind(Some(env.clone()), | |
214 | list!(vec![c[1].clone()]), | |
215 | vec![exc])?; | |
216 | eval(c[2].clone(), catch_env) | |
217 | }, | |
218 | _ => error("invalid catch block"), | |
219 | } | |
220 | }, | |
221 | res => res, | |
222 | } | |
223 | }, | |
224 | Sym(ref a0sym) if a0sym == "do" => { | |
225 | match eval_ast(&list!(l[1..l.len()-1].to_vec()), &env)? { | |
226 | List(_,_) => { | |
227 | ast = l.last().unwrap_or(&Nil).clone(); | |
228 | continue 'tco; | |
229 | }, | |
230 | _ => error("invalid do form"), | |
231 | } | |
232 | }, | |
233 | Sym(ref a0sym) if a0sym == "if" => { | |
234 | let cond = eval(l[1].clone(), env.clone())?; | |
235 | match cond { | |
236 | Bool(false) | Nil if l.len() >= 4 => { | |
237 | ast = l[3].clone(); | |
238 | continue 'tco; | |
239 | }, | |
240 | Bool(false) | Nil => Ok(Nil), | |
241 | _ if l.len() >= 3 => { | |
242 | ast = l[2].clone(); | |
243 | continue 'tco; | |
244 | }, | |
245 | _ => Ok(Nil) | |
246 | } | |
247 | }, | |
248 | Sym(ref a0sym) if a0sym == "fn*" => { | |
249 | let (a1, a2) = (l[1].clone(), l[2].clone()); | |
250 | Ok(MalFunc{eval: eval, ast: Rc::new(a2), env: env, | |
251 | params: Rc::new(a1), is_macro: false, | |
252 | meta: Rc::new(Nil)}) | |
253 | }, | |
254 | Sym(ref a0sym) if a0sym == "eval" => { | |
255 | ast = eval(l[1].clone(), env.clone())?; | |
256 | while let Some(ref e) = env.clone().outer { | |
257 | env = e.clone(); | |
258 | } | |
259 | continue 'tco; | |
260 | }, | |
261 | _ => { | |
262 | match eval_ast(&ast, &env)? { | |
263 | List(ref el,_) => { | |
264 | let ref f = el[0].clone(); | |
265 | let args = el[1..].to_vec(); | |
266 | match f { | |
267 | Func(_,_) => f.apply(args), | |
268 | MalFunc{ast: mast, env: menv, params, ..} => { | |
269 | let a = &**mast; | |
270 | let p = &**params; | |
271 | env = env_bind(Some(menv.clone()), p.clone(), args)?; | |
272 | ast = a.clone(); | |
273 | continue 'tco; | |
274 | }, | |
275 | _ => error("attempt to call non-function"), | |
276 | } | |
277 | }, | |
278 | _ => { | |
279 | error("expected a list") | |
280 | } | |
281 | } | |
282 | } | |
283 | } | |
284 | }, | |
285 | _ => eval_ast(&ast, &env), | |
286 | }; | |
287 | ||
288 | break; | |
289 | ||
290 | } // end 'tco loop | |
291 | ||
292 | ret | |
293 | } | |
294 | ||
295 | ||
296 | fn print(ast: &MalVal) -> String { | |
297 | ast.pr_str(true) | |
298 | } | |
299 | ||
300 | fn rep(str: &str, env: &Env) -> Result<String,MalErr> { | |
301 | let ast = read(str)?; | |
302 | let exp = eval(ast, env.clone())?; | |
303 | Ok(print(&exp)) | |
304 | } | |
305 | ||
306 | fn main() { | |
307 | let mut args = std::env::args(); | |
308 | let arg1 = args.nth(1); | |
309 | ||
310 | // `()` can be used when no completer is required | |
311 | let mut rl = Editor::<()>::new(); | |
312 | if rl.load_history(".mal-history").is_err() { | |
313 | println!("No previous history."); | |
314 | } | |
315 | ||
316 | // core.rs: defined using rust | |
317 | let repl_env = env_new(None); | |
318 | for (k, v) in core::ns() { | |
319 | env_sets(&repl_env, k, v); | |
320 | } | |
321 | env_sets(&repl_env, "*ARGV*", list!(args.map(Str).collect())); | |
322 | ||
323 | // core.mal: defined using the language itself | |
324 | let _ = rep("(def! not (fn* (a) (if a false true)))", &repl_env); | |
325 | let _ = rep("(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \")\")))))", &repl_env); | |
326 | let _ = rep("(defmacro! cond (fn* (& xs) (if (> (count xs) 0) (list 'if (first xs) (if (> (count xs) 1) (nth xs 1) (throw \"odd number of forms to cond\")) (cons 'cond (rest (rest xs)))))))", &repl_env); | |
327 | let _ = rep("(defmacro! or (fn* (& xs) (if (empty? xs) nil (if (= 1 (count xs)) (first xs) `(let* (or_FIXME ~(first xs)) (if or_FIXME or_FIXME (or ~@(rest xs))))))))", &repl_env); | |
328 | ||
329 | ||
330 | // Invoked with arguments | |
331 | if let Some(f) = arg1 { | |
332 | match rep(&format!("(load-file \"{}\")",f), &repl_env) { | |
333 | Ok(_) => std::process::exit(0), | |
334 | Err(e) => { | |
335 | println!("Error: {}", format_error(e)); | |
336 | std::process::exit(1); | |
337 | } | |
338 | } | |
339 | } | |
340 | ||
341 | // main repl loop | |
342 | loop { | |
343 | let readline = rl.readline("user> "); | |
344 | match readline { | |
345 | Ok(line) => { | |
346 | rl.add_history_entry(&line); | |
347 | rl.save_history(".mal-history").unwrap(); | |
348 | if line.len() > 0 { | |
349 | match rep(&line, &repl_env) { | |
350 | Ok(out) => println!("{}", out), | |
351 | Err(e) => println!("Error: {}", format_error(e)), | |
352 | } | |
353 | } | |
354 | }, | |
355 | Err(ReadlineError::Interrupted) => continue, | |
356 | Err(ReadlineError::Eof) => break, | |
357 | Err(err) => { | |
358 | println!("Error: {:?}", err); | |
359 | break | |
360 | } | |
361 | } | |
362 | } | |
363 | } | |
364 | ||
365 | // vim: ts=2:sw=2:expandtab |