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1d166495 JM |
1 | import types.Types.MalType; |
2 | import types.Types.*; | |
3 | import reader.*; | |
4 | import printer.*; | |
5 | import env.*; | |
6 | import core.*; | |
7 | ||
8 | class Step8_macros { | |
9 | // READ | |
10 | static function READ(str:String):MalType { | |
11 | return Reader.read_str(str); | |
12 | } | |
13 | ||
14 | // EVAL | |
15 | static function is_pair(ast:MalType) { | |
16 | return switch (ast) { | |
17 | case MalList(l) | MalVector(l): l.length > 0; | |
18 | case _: false; | |
19 | } | |
20 | } | |
21 | ||
22 | static function quasiquote(ast:MalType) { | |
23 | if (!is_pair(ast)) { | |
24 | return MalList([MalSymbol("quote"), ast]); | |
25 | } else { | |
26 | var a0 = first(ast); | |
27 | if (_equal_Q(a0, MalSymbol("unquote"))) { | |
28 | return _nth(ast, 1); | |
29 | } else if (is_pair(a0)) { | |
30 | var a00 = first(a0); | |
31 | if (_equal_Q(a00, MalSymbol("splice-unquote"))) { | |
32 | return MalList([MalSymbol("concat"), | |
33 | _nth(a0, 1), | |
34 | quasiquote(rest(ast))]); | |
35 | } | |
36 | } | |
37 | return MalList([MalSymbol("cons"), | |
38 | quasiquote(a0), | |
39 | quasiquote(rest(ast))]); | |
40 | } | |
41 | } | |
42 | ||
43 | static function is_macro(ast:MalType, env:Env) { | |
44 | return switch(ast) { | |
45 | case MalList(a): | |
46 | var a0 = a[0]; | |
47 | return symbol_Q(a0) && | |
48 | env.find(a0) != null && | |
49 | _macro_Q(env.get(a0)); | |
50 | case _: false; | |
51 | } | |
52 | } | |
53 | ||
54 | static function macroexpand(ast:MalType, env:Env) { | |
55 | while (is_macro(ast, env)) { | |
56 | var mac = env.get(first(ast)); | |
57 | switch (mac) { | |
58 | case MalFunc(f,_,_,_,_,_): | |
59 | ast = f(_list(ast).slice(1)); | |
60 | case _: break; | |
61 | } | |
62 | } | |
63 | return ast; | |
64 | } | |
65 | ||
66 | static function eval_ast(ast:MalType, env:Env) { | |
67 | return switch (ast) { | |
68 | case MalSymbol(s): env.get(ast); | |
69 | case MalList(l): | |
70 | MalList(l.map(function(x) { return EVAL(x, env); })); | |
71 | case MalVector(l): | |
72 | MalVector(l.map(function(x) { return EVAL(x, env); })); | |
73 | case MalHashMap(m): | |
74 | var new_map = new Map<String,MalType>(); | |
75 | for (k in m.keys()) { | |
76 | new_map[k] = EVAL(m[k], env); | |
77 | } | |
78 | MalHashMap(new_map); | |
79 | case _: ast; | |
80 | } | |
81 | } | |
82 | ||
83 | static function EVAL(ast:MalType, env:Env):MalType { | |
84 | while (true) { | |
85 | if (!list_Q(ast)) { return eval_ast(ast, env); } | |
86 | ||
87 | // apply | |
88 | ast = macroexpand(ast, env); | |
89 | if (!list_Q(ast)) { return ast; } | |
90 | ||
91 | var alst = _list(ast); | |
92 | switch (alst[0]) { | |
93 | case MalSymbol("def!"): | |
94 | return env.set(alst[1], EVAL(alst[2], env)); | |
95 | case MalSymbol("let*"): | |
96 | var let_env = new Env(env); | |
97 | switch (alst[1]) { | |
98 | case MalList(l) | MalVector(l): | |
99 | for (i in 0...l.length) { | |
100 | if ((i%2) > 0) { continue; } | |
101 | let_env.set(l[i], EVAL(l[i+1], let_env)); | |
102 | } | |
103 | case _: throw "Invalid let*"; | |
104 | } | |
105 | ast = alst[2]; | |
106 | env = let_env; | |
107 | continue; // TCO | |
108 | case MalSymbol("quote"): | |
109 | return alst[1]; | |
110 | case MalSymbol("quasiquote"): | |
111 | ast = quasiquote(alst[1]); | |
112 | continue; // TCO | |
113 | case MalSymbol("defmacro!"): | |
114 | var func = EVAL(alst[2], env); | |
115 | return switch (func) { | |
116 | case MalFunc(f,ast,e,params,_,_): | |
117 | env.set(alst[1], MalFunc(f,ast,e,params,true,nil)); | |
118 | case _: | |
119 | throw "Invalid defmacro! call"; | |
120 | } | |
121 | case MalSymbol("macroexpand"): | |
122 | return macroexpand(alst[1], env); | |
123 | case MalSymbol("do"): | |
124 | var el = eval_ast(MalList(alst.slice(1, alst.length-1)), env); | |
125 | ast = last(ast); | |
126 | continue; // TCO | |
127 | case MalSymbol("if"): | |
128 | var cond = EVAL(alst[1], env); | |
129 | if (cond != MalFalse && cond != MalNil) { | |
130 | ast = alst[2]; | |
131 | } else if (alst.length > 3) { | |
132 | ast = alst[3]; | |
133 | } else { | |
134 | return MalNil; | |
135 | } | |
136 | continue; // TCO | |
137 | case MalSymbol("fn*"): | |
138 | return MalFunc(function (args) { | |
139 | return EVAL(alst[2], new Env(env, _list(alst[1]), args)); | |
140 | },alst[2],env,alst[1],false,nil); | |
141 | case _: | |
142 | var el = eval_ast(ast, env); | |
143 | var lst = _list(el); | |
144 | switch (first(el)) { | |
145 | case MalFunc(f,a,e,params,_,_): | |
146 | var args = _list(el).slice(1); | |
147 | if (a != null) { | |
148 | ast = a; | |
149 | env = new Env(e, _list(params), args); | |
150 | continue; // TCO | |
151 | } else { | |
152 | return f(args); | |
153 | } | |
154 | case _: throw "Call of non-function"; | |
155 | } | |
156 | } | |
157 | } | |
158 | } | |
159 | ||
160 | ||
161 | static function PRINT(exp:MalType):String { | |
162 | return Printer.pr_str(exp, true); | |
163 | } | |
164 | ||
165 | // repl | |
166 | static var repl_env = new Env(null); | |
167 | ||
168 | static function rep(line:String):String { | |
169 | return PRINT(EVAL(READ(line), repl_env)); | |
170 | } | |
171 | ||
172 | public static function main() { | |
173 | #if js | |
174 | #error "JS not supported yet" | |
175 | #end | |
176 | ||
177 | // core.EXT: defined using Haxe | |
178 | for (k in Core.ns.keys()) { | |
179 | repl_env.set(MalSymbol(k), MalFunc(Core.ns[k],null,null,null,false,nil)); | |
180 | } | |
181 | ||
182 | var evalfn = MalFunc(function(args) { | |
183 | return EVAL(args[0], repl_env); | |
184 | },null,null,null,false,nil); | |
185 | repl_env.set(MalSymbol("eval"), evalfn); | |
186 | ||
187 | var cmdargs = Sys.args().map(function(a) { return MalString(a); }); | |
188 | repl_env.set(MalSymbol("*ARGV*"), MalList(cmdargs)); | |
189 | ||
190 | // core.mal: defined using the language itself | |
191 | rep("(def! not (fn* (a) (if a false true)))"); | |
192 | rep("(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \")\")))))"); | |
193 | 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)))))))"); | |
194 | 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))))))))"); | |
195 | ||
196 | ||
197 | if (cmdargs.length > 0) { | |
198 | rep('(load-file "${Sys.args()[0]}")'); | |
199 | Sys.exit(0); | |
200 | } | |
201 | ||
202 | while (true) { | |
203 | try { | |
204 | Sys.print("user> "); | |
205 | var line = Sys.stdin().readLine(); | |
206 | if (line == "") { continue; } | |
207 | Sys.println(rep(line)); | |
208 | } catch (exc:BlankLine) { | |
209 | continue; | |
210 | } catch (exc:haxe.io.Eof) { | |
211 | Sys.exit(0); | |
212 | } catch (exc:Dynamic) { | |
213 | Sys.println(exc); | |
214 | } | |
215 | } | |
216 | } | |
217 | } |