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f82cb965 DM |
1 | module main; |
2 | ||
3 | import std.algorithm; | |
4 | import std.array; | |
5 | import std.range; | |
6 | import std.stdio; | |
7 | import std.string; | |
8 | import std.c.process; | |
9 | import env; | |
10 | import mal_core; | |
11 | import readline; | |
12 | import reader; | |
13 | import printer; | |
14 | import types; | |
15 | ||
16 | bool is_pair(MalType ast) | |
17 | { | |
18 | auto lst = cast(MalSequential) ast; | |
19 | if (lst is null) return false; | |
20 | return lst.elements.length > 0; | |
21 | } | |
22 | ||
23 | MalType quasiquote(MalType ast) | |
24 | { | |
25 | if (!is_pair(ast)) | |
26 | { | |
27 | return new MalList([sym_quote, ast]); | |
28 | } | |
29 | auto ast_seq = verify_cast!MalSequential(ast); | |
30 | auto aste = ast_seq.elements; | |
31 | if (aste[0] == sym_unquote) | |
32 | { | |
33 | return aste[1]; | |
34 | } | |
35 | ||
36 | if (is_pair(aste[0])) | |
37 | { | |
38 | auto ast0_seq = verify_cast!MalSequential(aste[0]); | |
39 | if (ast0_seq.elements[0] == sym_splice_unquote) | |
40 | { | |
41 | return new MalList([new MalSymbol("concat"), ast0_seq.elements[1], quasiquote(new MalList(aste[1..$]))]); | |
42 | } | |
43 | } | |
44 | ||
45 | return new MalList([new MalSymbol("cons"), quasiquote(aste[0]), quasiquote(new MalList(aste[1..$]))]); | |
46 | } | |
47 | ||
48 | bool is_macro_call(MalType ast, Env env) | |
49 | { | |
50 | auto lst = cast(MalList) ast; | |
51 | if (lst is null) return false; | |
52 | if (lst.elements.length == 0) return false; | |
53 | auto sym0 = cast(MalSymbol) lst.elements[0]; | |
54 | if (sym0 is null) return false; | |
55 | if (env.find(sym0) is null) return false; | |
56 | auto val = env.get(sym0); | |
57 | auto val_func = cast(MalFunc) val; | |
58 | if (val_func is null) return false; | |
59 | return val_func.is_macro; | |
60 | } | |
61 | ||
62 | MalType macroexpand(MalType ast, Env env) | |
63 | { | |
64 | while (is_macro_call(ast, env)) | |
65 | { | |
66 | auto ast_list = verify_cast!MalList(ast); | |
67 | auto sym0 = verify_cast!MalSymbol(ast_list.elements[0]); | |
68 | auto macrofunc = verify_cast!MalFunc(env.get(sym0)); | |
69 | auto rest = ast_list.elements[1..$]; | |
70 | auto callenv = new Env(macrofunc.def_env, macrofunc.arg_names, rest); | |
71 | ast = EVAL(macrofunc.func_body, callenv); | |
72 | } | |
73 | return ast; | |
74 | } | |
75 | ||
76 | MalType READ(string str) | |
77 | { | |
78 | return read_str(str); | |
79 | } | |
80 | ||
81 | MalType eval_ast(MalType ast, Env env) | |
82 | { | |
83 | if (typeid(ast) == typeid(MalSymbol)) | |
84 | { | |
85 | auto sym = verify_cast!MalSymbol(ast); | |
86 | return env.get(sym); | |
87 | } | |
88 | else if (typeid(ast) == typeid(MalList)) | |
89 | { | |
90 | auto lst = verify_cast!MalList(ast); | |
91 | auto el = array(lst.elements.map!(e => EVAL(e, env))); | |
92 | return new MalList(el); | |
93 | } | |
94 | else if (typeid(ast) == typeid(MalVector)) | |
95 | { | |
96 | auto lst = verify_cast!MalVector(ast); | |
97 | auto el = array(lst.elements.map!(e => EVAL(e, env))); | |
98 | return new MalVector(el); | |
99 | } | |
100 | else if (typeid(ast) == typeid(MalHashmap)) | |
101 | { | |
102 | auto hm = verify_cast!MalHashmap(ast); | |
103 | typeof(hm.data) new_data; | |
104 | foreach (string k, MalType v; hm.data) | |
105 | { | |
106 | new_data[k] = EVAL(v, env); | |
107 | } | |
108 | return new MalHashmap(new_data); | |
109 | } | |
110 | else | |
111 | { | |
112 | return ast; | |
113 | } | |
114 | } | |
115 | ||
116 | MalType EVAL(MalType ast, Env env) | |
117 | { | |
118 | for (;;) | |
119 | { | |
120 | MalList ast_list = cast(MalList) ast; | |
121 | if (ast_list is null) | |
122 | { | |
123 | return eval_ast(ast, env); | |
124 | } | |
125 | ||
126 | ast = macroexpand(ast, env); | |
127 | ast_list = cast(MalList) ast; | |
128 | if (ast_list is null) | |
129 | { | |
130 | return ast; | |
131 | } | |
132 | ||
133 | auto aste = ast_list.elements; | |
134 | auto a0_sym = cast(MalSymbol) aste[0]; | |
135 | auto sym_name = a0_sym is null ? "" : a0_sym.name; | |
136 | switch (sym_name) | |
137 | { | |
138 | case "def!": | |
139 | auto a1 = verify_cast!MalSymbol(aste[1]); | |
140 | return env.set(a1, EVAL(aste[2], env)); | |
141 | ||
142 | case "let*": | |
143 | auto a1 = verify_cast!MalSequential(aste[1]); | |
144 | auto let_env = new Env(env); | |
145 | foreach (kv; chunks(a1.elements, 2)) | |
146 | { | |
147 | if (kv.length < 2) throw new Exception("let* requires even number of elements"); | |
148 | auto var_name = verify_cast!MalSymbol(kv[0]); | |
149 | let_env.set(var_name, EVAL(kv[1], let_env)); | |
150 | } | |
151 | ast = aste[2]; | |
152 | env = let_env; | |
153 | continue; // TCO | |
154 | ||
155 | case "quote": | |
156 | return aste[1]; | |
157 | ||
158 | case "quasiquote": | |
159 | ast = quasiquote(aste[1]); | |
160 | continue; // TCO | |
161 | ||
162 | case "defmacro!": | |
163 | auto a1 = verify_cast!MalSymbol(aste[1]); | |
164 | auto mac = verify_cast!MalFunc(EVAL(aste[2], env)); | |
165 | mac.is_macro = true; | |
166 | return env.set(a1, mac); | |
167 | ||
168 | case "macroexpand": | |
169 | return macroexpand(aste[1], env); | |
170 | ||
171 | case "try*": | |
172 | MalType exc; | |
173 | try | |
174 | { | |
175 | return EVAL(aste[1], env); | |
176 | } | |
177 | catch (MalException e) | |
178 | { | |
179 | exc = e.data; | |
180 | } | |
181 | catch (Exception e) | |
182 | { | |
183 | exc = new MalString(e.msg); | |
184 | } | |
185 | if (aste.length < 3) return mal_nil; | |
186 | auto catch_clause = verify_cast!MalList(aste[2]); | |
187 | auto catch_env = new Env(env, [catch_clause.elements[1]], [exc]); | |
188 | return EVAL(catch_clause.elements[2], catch_env); | |
189 | ||
190 | case "do": | |
191 | auto all_but_last = new MalList(aste[1..$-1]); | |
192 | eval_ast(all_but_last, env); | |
193 | ast = aste[$-1]; | |
194 | continue; // TCO | |
195 | ||
196 | case "if": | |
197 | auto cond = EVAL(aste[1], env); | |
198 | if (cond.is_truthy()) | |
199 | { | |
200 | ast = aste[2]; | |
201 | continue; // TCO | |
202 | } | |
203 | else | |
204 | if (aste.length > 3) | |
205 | { | |
206 | ast = aste[3]; | |
207 | continue; // TCO | |
208 | } | |
209 | else | |
210 | { | |
211 | return mal_nil; | |
212 | } | |
213 | ||
214 | case "fn*": | |
215 | auto args_list = verify_cast!MalSequential(aste[1]); | |
216 | return new MalFunc(args_list.elements, aste[2], env); | |
217 | ||
218 | default: | |
219 | auto el = verify_cast!MalList(eval_ast(ast, env)); | |
220 | if (el.elements.length == 0) | |
221 | { | |
222 | throw new Exception("Expected a non-empty list"); | |
223 | } | |
224 | auto first = el.elements[0]; | |
225 | auto rest = el.elements[1..$]; | |
226 | if (typeid(first) == typeid(MalFunc)) | |
227 | { | |
228 | auto funcobj = verify_cast!MalFunc(first); | |
229 | auto callenv = new Env(funcobj.def_env, funcobj.arg_names, rest); | |
230 | ast = funcobj.func_body; | |
231 | env = callenv; | |
232 | continue; // TCO | |
233 | } | |
234 | else if (typeid(first) == typeid(MalBuiltinFunc)) | |
235 | { | |
236 | auto builtinfuncobj = verify_cast!MalBuiltinFunc(first); | |
237 | return builtinfuncobj.fn(rest); | |
238 | } | |
239 | else | |
240 | { | |
241 | throw new Exception("Expected a function"); | |
242 | } | |
243 | } | |
244 | } | |
245 | } | |
246 | ||
247 | string PRINT(MalType ast) | |
248 | { | |
249 | return pr_str(ast); | |
250 | } | |
251 | ||
252 | MalType re(string str, Env env) | |
253 | { | |
254 | return EVAL(READ(str), env); | |
255 | } | |
256 | ||
257 | string rep(string str, Env env) | |
258 | { | |
259 | return PRINT(re(str, env)); | |
260 | } | |
261 | ||
262 | static MalList create_argv_list(string[] args) | |
263 | { | |
264 | if (args.length <= 2) return new MalList([]); | |
265 | return new MalList(array(args[2..$].map!(s => cast(MalType)(new MalString(s))))); | |
266 | } | |
267 | ||
268 | void main(string[] args) | |
269 | { | |
270 | Env repl_env = new Env(null); | |
271 | foreach (string sym_name, BuiltinStaticFuncType f; core_ns) | |
272 | { | |
273 | repl_env.set(new MalSymbol(sym_name), new MalBuiltinFunc(f, sym_name)); | |
274 | } | |
275 | ||
276 | BuiltinFuncType eval_func = (a ...) { | |
277 | verify_args_count(a, 1); | |
278 | return EVAL(a[0], repl_env); | |
279 | }; | |
280 | repl_env.set(new MalSymbol("eval"), new MalBuiltinFunc(eval_func, "eval")); | |
281 | repl_env.set(new MalSymbol("*ARGV*"), create_argv_list(args)); | |
282 | ||
283 | // core.mal: defined using the language itself | |
284 | re("(def! not (fn* (a) (if a false true)))", repl_env); | |
285 | re("(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \")\")))))", repl_env); | |
286 | re("(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); | |
287 | re("(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); | |
288 | ||
289 | if (args.length > 1) | |
290 | { | |
291 | try | |
292 | { | |
293 | rep("(load-file \"" ~ args[1] ~ "\")", repl_env); | |
294 | return; | |
295 | } | |
296 | catch (Exception e) | |
297 | { | |
298 | writeln("Error: ", e.msg); | |
299 | std.c.process.exit(1); | |
300 | } | |
301 | } | |
302 | ||
303 | for (;;) | |
304 | { | |
305 | string line = _readline("user> "); | |
306 | if (line is null) break; | |
307 | if (line.length == 0) continue; | |
308 | try | |
309 | { | |
310 | writeln(rep(line, repl_env)); | |
311 | } | |
312 | catch (Exception e) | |
313 | { | |
314 | writeln("Error: ", e.msg); | |
315 | } | |
316 | } | |
317 | writeln(""); | |
318 | } |