Commit | Line | Data |
---|---|---|
ad0fc149 ST |
1 | #include "MAL.h" |
2 | ||
3 | #include "Environment.h" | |
4 | #include "ReadLine.h" | |
5 | #include "Types.h" | |
6 | ||
7 | #include <iostream> | |
8 | #include <memory> | |
9 | ||
10 | malValuePtr READ(const String& input); | |
11 | String PRINT(malValuePtr ast); | |
12 | static void installFunctions(malEnvPtr env); | |
13 | ||
14 | static ReadLine s_readLine("~/.mal-history"); | |
15 | ||
16 | int main(int argc, char* argv[]) | |
17 | { | |
18 | String prompt = "user> "; | |
19 | String input; | |
20 | malEnvPtr replEnv(new malEnv); | |
21 | installCore(replEnv); | |
22 | installFunctions(replEnv); | |
23 | while (s_readLine.get(prompt, input)) { | |
24 | String out; | |
25 | try { | |
26 | out = rep(input, replEnv); | |
27 | } | |
28 | catch (malEmptyInputException&) { | |
29 | continue; // no output | |
30 | } | |
31 | catch (String& s) { | |
32 | out = s; | |
33 | }; | |
34 | std::cout << out << "\n"; | |
35 | } | |
36 | return 0; | |
37 | } | |
38 | ||
39 | String rep(const String& input, malEnvPtr env) | |
40 | { | |
41 | return PRINT(EVAL(READ(input), env)); | |
42 | } | |
43 | ||
44 | malValuePtr READ(const String& input) | |
45 | { | |
46 | return readStr(input); | |
47 | } | |
48 | ||
49 | malValuePtr EVAL(malValuePtr ast, malEnvPtr env) | |
50 | { | |
51 | const malList* list = DYNAMIC_CAST(malList, ast); | |
52 | if (!list || (list->count() == 0)) { | |
53 | return ast->eval(env); | |
54 | } | |
55 | ||
56 | // From here on down we are evaluating a non-empty list. | |
57 | // First handle the special forms. | |
58 | if (const malSymbol* symbol = DYNAMIC_CAST(malSymbol, list->item(0))) { | |
59 | String special = symbol->value(); | |
60 | int argCount = list->count() - 1; | |
61 | ||
62 | if (special == "def!") { | |
63 | checkArgsIs("def!", 2, argCount); | |
64 | const malSymbol* id = VALUE_CAST(malSymbol, list->item(1)); | |
65 | return env->set(id->value(), EVAL(list->item(2), env)); | |
66 | } | |
67 | ||
68 | if (special == "do") { | |
69 | checkArgsAtLeast("do", 1, argCount); | |
70 | ||
71 | for (int i = 1; i < argCount; i++) { | |
72 | EVAL(list->item(i), env); | |
73 | } | |
74 | return EVAL(list->item(argCount), env); | |
75 | } | |
76 | ||
77 | if (special == "fn*") { | |
78 | checkArgsIs("fn*", 2, argCount); | |
79 | ||
80 | const malSequence* bindings = | |
81 | VALUE_CAST(malSequence, list->item(1)); | |
82 | StringVec params; | |
83 | for (int i = 0; i < bindings->count(); i++) { | |
84 | const malSymbol* sym = | |
85 | VALUE_CAST(malSymbol, bindings->item(i)); | |
86 | params.push_back(sym->value()); | |
87 | } | |
88 | ||
89 | return mal::lambda(params, list->item(2), env); | |
90 | } | |
91 | ||
92 | if (special == "if") { | |
93 | checkArgsBetween("if", 2, 3, argCount); | |
94 | ||
95 | bool isTrue = EVAL(list->item(1), env)->isTrue(); | |
96 | if (!isTrue && (argCount == 2)) { | |
97 | return mal::nilValue(); | |
98 | } | |
99 | return EVAL(list->item(isTrue ? 2 : 3), env); | |
100 | } | |
101 | ||
102 | if (special == "let*") { | |
103 | checkArgsIs("let*", 2, argCount); | |
104 | const malSequence* bindings = | |
105 | VALUE_CAST(malSequence, list->item(1)); | |
106 | int count = checkArgsEven("let*", bindings->count()); | |
107 | malEnvPtr inner(new malEnv(env)); | |
108 | for (int i = 0; i < count; i += 2) { | |
109 | const malSymbol* var = | |
110 | VALUE_CAST(malSymbol, bindings->item(i)); | |
111 | inner->set(var->value(), EVAL(bindings->item(i+1), inner)); | |
112 | } | |
113 | return EVAL(list->item(2), inner); | |
114 | } | |
115 | } | |
116 | ||
117 | // Now we're left with the case of a regular list to be evaluated. | |
118 | std::unique_ptr<malValueVec> items(list->evalItems(env)); | |
119 | malValuePtr op = items->at(0); | |
120 | if (const malLambda* lambda = DYNAMIC_CAST(malLambda, op)) { | |
121 | return EVAL(lambda->getBody(), | |
122 | lambda->makeEnv(items->begin()+1, items->end())); | |
123 | } | |
124 | else { | |
125 | return APPLY(op, items->begin()+1, items->end(), env); | |
126 | } | |
127 | } | |
128 | ||
129 | String PRINT(malValuePtr ast) | |
130 | { | |
131 | return ast->print(true); | |
132 | } | |
133 | ||
134 | malValuePtr APPLY(malValuePtr op, malValueIter argsBegin, malValueIter argsEnd, | |
135 | malEnvPtr env) | |
136 | { | |
137 | const malApplicable* handler = DYNAMIC_CAST(malApplicable, op); | |
138 | ASSERT(handler != NULL, "\"%s\" is not applicable", op->print(true).c_str()); | |
139 | ||
140 | return handler->apply(argsBegin, argsEnd, env); | |
141 | } | |
142 | ||
143 | static const char* malFunctionTable[] = { | |
144 | "(def! list (fn* (& items) items))", | |
145 | "(def! not (fn* (cond) (if cond false true)))", | |
146 | "(def! >= (fn* (a b) (<= b a)))", | |
147 | "(def! < (fn* (a b) (not (<= b a))))", | |
148 | "(def! > (fn* (a b) (not (<= a b))))", | |
149 | }; | |
150 | ||
151 | static void installFunctions(malEnvPtr env) { | |
f01c2683 ST |
152 | for (auto &function : malFunctionTable) { |
153 | rep(function, env); | |
ad0fc149 ST |
154 | } |
155 | } | |
cb252845 ST |
156 | |
157 | // Added to keep the linker happy at step A | |
158 | malValuePtr readline(const String& prompt) | |
159 | { | |
160 | String input; | |
161 | if (s_readLine.get(prompt, input)) { | |
162 | return mal::string(input); | |
163 | } | |
164 | return mal::nilValue(); | |
165 | } | |
166 |