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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 | MalType READ(string str) | |
49 | { | |
50 | return read_str(str); | |
51 | } | |
52 | ||
53 | MalType eval_ast(MalType ast, Env env) | |
54 | { | |
55 | if (typeid(ast) == typeid(MalSymbol)) | |
56 | { | |
57 | auto sym = verify_cast!MalSymbol(ast); | |
58 | return env.get(sym); | |
59 | } | |
60 | else if (typeid(ast) == typeid(MalList)) | |
61 | { | |
62 | auto lst = verify_cast!MalList(ast); | |
63 | auto el = array(lst.elements.map!(e => EVAL(e, env))); | |
64 | return new MalList(el); | |
65 | } | |
66 | else if (typeid(ast) == typeid(MalVector)) | |
67 | { | |
68 | auto lst = verify_cast!MalVector(ast); | |
69 | auto el = array(lst.elements.map!(e => EVAL(e, env))); | |
70 | return new MalVector(el); | |
71 | } | |
72 | else if (typeid(ast) == typeid(MalHashmap)) | |
73 | { | |
74 | auto hm = verify_cast!MalHashmap(ast); | |
75 | typeof(hm.data) new_data; | |
76 | foreach (string k, MalType v; hm.data) | |
77 | { | |
78 | new_data[k] = EVAL(v, env); | |
79 | } | |
80 | return new MalHashmap(new_data); | |
81 | } | |
82 | else | |
83 | { | |
84 | return ast; | |
85 | } | |
86 | } | |
87 | ||
88 | MalType EVAL(MalType ast, Env env) | |
89 | { | |
90 | for (;;) | |
91 | { | |
92 | MalList ast_list = cast(MalList) ast; | |
93 | if (ast_list is null) | |
94 | { | |
95 | return eval_ast(ast, env); | |
96 | } | |
97 | ||
98 | auto aste = ast_list.elements; | |
99 | auto a0_sym = cast(MalSymbol) aste[0]; | |
100 | auto sym_name = a0_sym is null ? "" : a0_sym.name; | |
101 | switch (sym_name) | |
102 | { | |
103 | case "def!": | |
104 | auto a1 = verify_cast!MalSymbol(aste[1]); | |
105 | return env.set(a1, EVAL(aste[2], env)); | |
106 | ||
107 | case "let*": | |
108 | auto a1 = verify_cast!MalSequential(aste[1]); | |
109 | auto let_env = new Env(env); | |
110 | foreach (kv; chunks(a1.elements, 2)) | |
111 | { | |
112 | if (kv.length < 2) throw new Exception("let* requires even number of elements"); | |
113 | auto var_name = verify_cast!MalSymbol(kv[0]); | |
114 | let_env.set(var_name, EVAL(kv[1], let_env)); | |
115 | } | |
116 | ast = aste[2]; | |
117 | env = let_env; | |
118 | continue; // TCO | |
119 | ||
120 | case "quote": | |
121 | return aste[1]; | |
122 | ||
123 | case "quasiquote": | |
124 | ast = quasiquote(aste[1]); | |
125 | continue; // TCO | |
126 | ||
127 | case "do": | |
128 | auto all_but_last = new MalList(aste[1..$-1]); | |
129 | eval_ast(all_but_last, env); | |
130 | ast = aste[$-1]; | |
131 | continue; // TCO | |
132 | ||
133 | case "if": | |
134 | auto cond = EVAL(aste[1], env); | |
135 | if (cond.is_truthy()) | |
136 | { | |
137 | ast = aste[2]; | |
138 | continue; // TCO | |
139 | } | |
140 | else | |
141 | if (aste.length > 3) | |
142 | { | |
143 | ast = aste[3]; | |
144 | continue; // TCO | |
145 | } | |
146 | else | |
147 | { | |
148 | return mal_nil; | |
149 | } | |
150 | ||
151 | case "fn*": | |
152 | auto args_list = verify_cast!MalSequential(aste[1]); | |
153 | return new MalFunc(args_list.elements, aste[2], env); | |
154 | ||
155 | default: | |
156 | auto el = verify_cast!MalList(eval_ast(ast, env)); | |
157 | if (el.elements.length == 0) | |
158 | { | |
159 | throw new Exception("Expected a non-empty list"); | |
160 | } | |
161 | auto first = el.elements[0]; | |
162 | auto rest = el.elements[1..$]; | |
163 | if (typeid(first) == typeid(MalFunc)) | |
164 | { | |
165 | auto funcobj = verify_cast!MalFunc(first); | |
166 | auto callenv = new Env(funcobj.def_env, funcobj.arg_names, rest); | |
167 | ast = funcobj.func_body; | |
168 | env = callenv; | |
169 | continue; // TCO | |
170 | } | |
171 | else if (typeid(first) == typeid(MalBuiltinFunc)) | |
172 | { | |
173 | auto builtinfuncobj = verify_cast!MalBuiltinFunc(first); | |
174 | return builtinfuncobj.fn(rest); | |
175 | } | |
176 | else | |
177 | { | |
178 | throw new Exception("Expected a function"); | |
179 | } | |
180 | } | |
181 | } | |
182 | } | |
183 | ||
184 | string PRINT(MalType ast) | |
185 | { | |
186 | return pr_str(ast); | |
187 | } | |
188 | ||
189 | MalType re(string str, Env env) | |
190 | { | |
191 | return EVAL(READ(str), env); | |
192 | } | |
193 | ||
194 | string rep(string str, Env env) | |
195 | { | |
196 | return PRINT(re(str, env)); | |
197 | } | |
198 | ||
199 | static MalList create_argv_list(string[] args) | |
200 | { | |
201 | if (args.length <= 2) return new MalList([]); | |
202 | return new MalList(array(args[2..$].map!(s => cast(MalType)(new MalString(s))))); | |
203 | } | |
204 | ||
205 | void main(string[] args) | |
206 | { | |
207 | Env repl_env = new Env(null); | |
208 | foreach (string sym_name, BuiltinStaticFuncType f; core_ns) | |
209 | { | |
210 | repl_env.set(new MalSymbol(sym_name), new MalBuiltinFunc(f, sym_name)); | |
211 | } | |
212 | ||
213 | BuiltinFuncType eval_func = (a ...) { | |
214 | verify_args_count(a, 1); | |
215 | return EVAL(a[0], repl_env); | |
216 | }; | |
217 | repl_env.set(new MalSymbol("eval"), new MalBuiltinFunc(eval_func, "eval")); | |
218 | repl_env.set(new MalSymbol("*ARGV*"), create_argv_list(args)); | |
219 | ||
220 | // core.mal: defined using the language itself | |
221 | re("(def! not (fn* (a) (if a false true)))", repl_env); | |
222 | re("(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \")\")))))", repl_env); | |
223 | ||
224 | if (args.length > 1) | |
225 | { | |
226 | try | |
227 | { | |
228 | rep("(load-file \"" ~ args[1] ~ "\")", repl_env); | |
229 | return; | |
230 | } | |
231 | catch (Exception e) | |
232 | { | |
233 | writeln("Error: ", e.msg); | |
234 | std.c.process.exit(1); | |
235 | } | |
236 | } | |
237 | ||
238 | for (;;) | |
239 | { | |
240 | string line = _readline("user> "); | |
241 | if (line is null) break; | |
242 | if (line.length == 0) continue; | |
243 | try | |
244 | { | |
245 | writeln(rep(line, repl_env)); | |
246 | } | |
247 | catch (Exception e) | |
248 | { | |
249 | writeln("Error: ", e.msg); | |
250 | } | |
251 | } | |
252 | writeln(""); | |
253 | } |