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
|
if (typeof module !== 'undefined') {
var types = require('./types');
var readline = require('./node_readline');
var reader = require('./reader');
var printer = require('./printer');
var Env = require('./env').Env;
}
// read
function READ(str) {
return reader.read_str(str);
}
// eval
function eval_ast(ast, env) {
if (types._symbol_Q(ast)) {
return env.get(ast);
} else if (types._list_Q(ast)) {
return ast.map(function(a) { return EVAL(a, env); });
} else if (types._vector_Q(ast)) {
var v = ast.map(function(a) { return EVAL(a, env); });
v.__isvector__ = true;
return v;
} else if (types._hash_map_Q(ast)) {
var new_hm = {};
for (k in ast) {
new_hm[EVAL(k, env)] = EVAL(ast[k], env);
}
return new_hm;
} else {
return ast;
}
}
function _EVAL(ast, env) {
//printer.println("EVAL:", printer._pr_str(ast, true));
if (!types._list_Q(ast)) {
return eval_ast(ast, env);
}
// apply list
var a0 = ast[0], a1 = ast[1], a2 = ast[2], a3 = ast[3];
switch (a0.value) {
case "def!":
var res = EVAL(a2, env);
return env.set(a1, res);
case "let*":
var let_env = new Env(env);
for (var i=0; i < a1.length; i+=2) {
let_env.set(a1[i], EVAL(a1[i+1], let_env));
}
return EVAL(a2, let_env);
default:
var el = eval_ast(ast, env), f = el[0];
return f.apply(f, el.slice(1));
}
}
function EVAL(ast, env) {
var result = _EVAL(ast, env);
return (typeof result !== "undefined") ? result : null;
}
// print
function PRINT(exp) {
return printer._pr_str(exp, true);
}
// repl
var repl_env = new Env();
var rep = function(str) { return PRINT(EVAL(READ(str), repl_env)); };
repl_env.set(types._symbol('+'), function(a,b){return a+b;});
repl_env.set(types._symbol('-'), function(a,b){return a-b;});
repl_env.set(types._symbol('*'), function(a,b){return a*b;});
repl_env.set(types._symbol('/'), function(a,b){return a/b;});
// repl loop
if (typeof require !== 'undefined' && require.main === module) {
// Synchronous node.js commandline mode
while (true) {
var line = readline.readline("user> ");
if (line === null) { break; }
try {
if (line) { printer.println(rep(line)); }
} catch (exc) {
if (exc instanceof reader.BlankException) { continue; }
if (exc.stack) { printer.println(exc.stack); }
else { printer.println(exc); }
}
}
}
|
