Commit | Line | Data |
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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 | ||
494c1608 ST |
16 | static malEnvPtr replEnv(new malEnv); |
17 | ||
ad0fc149 ST |
18 | int main(int argc, char* argv[]) |
19 | { | |
20 | String prompt = "user> "; | |
21 | String input; | |
ad0fc149 ST |
22 | installCore(replEnv); |
23 | installFunctions(replEnv); | |
24 | while (s_readLine.get(prompt, input)) { | |
25 | String out; | |
26 | try { | |
27 | out = rep(input, replEnv); | |
28 | } | |
29 | catch (malEmptyInputException&) { | |
30 | continue; // no output | |
31 | } | |
32 | catch (String& s) { | |
33 | out = s; | |
34 | }; | |
35 | std::cout << out << "\n"; | |
36 | } | |
37 | return 0; | |
38 | } | |
39 | ||
40 | String rep(const String& input, malEnvPtr env) | |
41 | { | |
42 | return PRINT(EVAL(READ(input), env)); | |
43 | } | |
44 | ||
45 | malValuePtr READ(const String& input) | |
46 | { | |
47 | return readStr(input); | |
48 | } | |
49 | ||
50 | malValuePtr EVAL(malValuePtr ast, malEnvPtr env) | |
51 | { | |
494c1608 ST |
52 | if (!env) { |
53 | env = replEnv; | |
54 | } | |
ad0fc149 ST |
55 | const malList* list = DYNAMIC_CAST(malList, ast); |
56 | if (!list || (list->count() == 0)) { | |
57 | return ast->eval(env); | |
58 | } | |
59 | ||
60 | // From here on down we are evaluating a non-empty list. | |
61 | // First handle the special forms. | |
62 | if (const malSymbol* symbol = DYNAMIC_CAST(malSymbol, list->item(0))) { | |
63 | String special = symbol->value(); | |
64 | int argCount = list->count() - 1; | |
65 | ||
66 | if (special == "def!") { | |
67 | checkArgsIs("def!", 2, argCount); | |
68 | const malSymbol* id = VALUE_CAST(malSymbol, list->item(1)); | |
69 | return env->set(id->value(), EVAL(list->item(2), env)); | |
70 | } | |
71 | ||
72 | if (special == "do") { | |
73 | checkArgsAtLeast("do", 1, argCount); | |
74 | ||
75 | for (int i = 1; i < argCount; i++) { | |
76 | EVAL(list->item(i), env); | |
77 | } | |
78 | return EVAL(list->item(argCount), env); | |
79 | } | |
80 | ||
81 | if (special == "fn*") { | |
82 | checkArgsIs("fn*", 2, argCount); | |
83 | ||
84 | const malSequence* bindings = | |
85 | VALUE_CAST(malSequence, list->item(1)); | |
86 | StringVec params; | |
87 | for (int i = 0; i < bindings->count(); i++) { | |
88 | const malSymbol* sym = | |
89 | VALUE_CAST(malSymbol, bindings->item(i)); | |
90 | params.push_back(sym->value()); | |
91 | } | |
92 | ||
93 | return mal::lambda(params, list->item(2), env); | |
94 | } | |
95 | ||
96 | if (special == "if") { | |
97 | checkArgsBetween("if", 2, 3, argCount); | |
98 | ||
99 | bool isTrue = EVAL(list->item(1), env)->isTrue(); | |
100 | if (!isTrue && (argCount == 2)) { | |
101 | return mal::nilValue(); | |
102 | } | |
103 | return EVAL(list->item(isTrue ? 2 : 3), env); | |
104 | } | |
105 | ||
106 | if (special == "let*") { | |
107 | checkArgsIs("let*", 2, argCount); | |
108 | const malSequence* bindings = | |
109 | VALUE_CAST(malSequence, list->item(1)); | |
110 | int count = checkArgsEven("let*", bindings->count()); | |
111 | malEnvPtr inner(new malEnv(env)); | |
112 | for (int i = 0; i < count; i += 2) { | |
113 | const malSymbol* var = | |
114 | VALUE_CAST(malSymbol, bindings->item(i)); | |
115 | inner->set(var->value(), EVAL(bindings->item(i+1), inner)); | |
116 | } | |
117 | return EVAL(list->item(2), inner); | |
118 | } | |
119 | } | |
120 | ||
121 | // Now we're left with the case of a regular list to be evaluated. | |
122 | std::unique_ptr<malValueVec> items(list->evalItems(env)); | |
123 | malValuePtr op = items->at(0); | |
124 | if (const malLambda* lambda = DYNAMIC_CAST(malLambda, op)) { | |
125 | return EVAL(lambda->getBody(), | |
126 | lambda->makeEnv(items->begin()+1, items->end())); | |
127 | } | |
128 | else { | |
494c1608 | 129 | return APPLY(op, items->begin()+1, items->end()); |
ad0fc149 ST |
130 | } |
131 | } | |
132 | ||
133 | String PRINT(malValuePtr ast) | |
134 | { | |
135 | return ast->print(true); | |
136 | } | |
137 | ||
494c1608 | 138 | malValuePtr APPLY(malValuePtr op, malValueIter argsBegin, malValueIter argsEnd) |
ad0fc149 ST |
139 | { |
140 | const malApplicable* handler = DYNAMIC_CAST(malApplicable, op); | |
0997015d ST |
141 | MAL_CHECK(handler != NULL, |
142 | "\"%s\" is not applicable", op->print(true).c_str()); | |
ad0fc149 | 143 | |
494c1608 | 144 | return handler->apply(argsBegin, argsEnd); |
ad0fc149 ST |
145 | } |
146 | ||
147 | static const char* malFunctionTable[] = { | |
148 | "(def! list (fn* (& items) items))", | |
149 | "(def! not (fn* (cond) (if cond false true)))", | |
150 | "(def! >= (fn* (a b) (<= b a)))", | |
151 | "(def! < (fn* (a b) (not (<= b a))))", | |
152 | "(def! > (fn* (a b) (not (<= a b))))", | |
153 | }; | |
154 | ||
155 | static void installFunctions(malEnvPtr env) { | |
f01c2683 ST |
156 | for (auto &function : malFunctionTable) { |
157 | rep(function, env); | |
ad0fc149 ST |
158 | } |
159 | } | |
cb252845 ST |
160 | |
161 | // Added to keep the linker happy at step A | |
162 | malValuePtr readline(const String& prompt) | |
163 | { | |
164 | String input; | |
165 | if (s_readLine.get(prompt, input)) { | |
166 | return mal::string(input); | |
167 | } | |
168 | return mal::nilValue(); | |
169 | } | |
170 |