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| 1 part of petitparser.lisp; | |
| 2 | |
| 3 /// The native functions. | |
| 4 class Natives { | |
| 5 | |
| 6 /// Imports the native functions into the [environment]. | |
| 7 static Environment import(Environment environment) { | |
| 8 | |
| 9 // basic functions | |
| 10 environment.define(new Name('define'), _define); | |
| 11 environment.define(new Name('lambda'), _lambda); | |
| 12 environment.define(new Name('quote'), _quote); | |
| 13 environment.define(new Name('eval'), _eval); | |
| 14 environment.define(new Name('apply'), _apply); | |
| 15 environment.define(new Name('let'), _let); | |
| 16 environment.define(new Name('set!'), _set); | |
| 17 environment.define(new Name('print'), _print); | |
| 18 | |
| 19 // control structures | |
| 20 environment.define(new Name('if'), _if); | |
| 21 environment.define(new Name('while'), _while); | |
| 22 environment.define(new Name('and'), _and); | |
| 23 environment.define(new Name('or'), _or); | |
| 24 environment.define(new Name('not'), _not); | |
| 25 | |
| 26 // arithmetic operators | |
| 27 environment.define(new Name('+'), _plus); | |
| 28 environment.define(new Name('-'), _minus); | |
| 29 environment.define(new Name('*'), _multiply); | |
| 30 environment.define(new Name('/'), _divide); | |
| 31 environment.define(new Name('%'), _modulo); | |
| 32 | |
| 33 // arithmetic comparators | |
| 34 environment.define(new Name('<'), _smaller); | |
| 35 environment.define(new Name('<='), _smallerOrEqual); | |
| 36 environment.define(new Name('='), _equal); | |
| 37 environment.define(new Name('!='), _notEqual); | |
| 38 environment.define(new Name('>'), _larger); | |
| 39 environment.define(new Name('>='), _largerOrEqual); | |
| 40 | |
| 41 // list operators | |
| 42 environment.define(new Name('cons'), _cons); | |
| 43 environment.define(new Name('car'), _car); | |
| 44 environment.define(new Name('car!'), _carSet); | |
| 45 environment.define(new Name('cdr'), _cdr); | |
| 46 environment.define(new Name('cdr!'), _cdrSet); | |
| 47 | |
| 48 return environment; | |
| 49 } | |
| 50 | |
| 51 static _define(Environment env, args) { | |
| 52 if (args.head is Name) { | |
| 53 return env.define(args.head, evalList(env, args.tail)); | |
| 54 } else if (args.head.head is Name) { | |
| 55 return env.define( | |
| 56 args.head.head, _lambda(env, new Cons(args.head.tail, args.tail))); | |
| 57 } else { | |
| 58 throw new ArgumentError('Invalid define: $args'); | |
| 59 } | |
| 60 } | |
| 61 | |
| 62 static _lambda(Environment lambdaEnv, lambdaArgs) { | |
| 63 return (Environment evalEnv, evalArgs) { | |
| 64 var inner = lambdaEnv.create(); | |
| 65 var names = lambdaArgs.head; | |
| 66 var values = evalArguments(evalEnv, evalArgs); | |
| 67 while (names != null && values != null) { | |
| 68 inner.define(names.head, values.head); | |
| 69 names = names.tail; | |
| 70 values = values.tail; | |
| 71 } | |
| 72 return evalList(inner, lambdaArgs.tail); | |
| 73 }; | |
| 74 } | |
| 75 | |
| 76 static _quote(Environment env, args) { | |
| 77 return args; | |
| 78 } | |
| 79 | |
| 80 static _eval(Environment env, args) { | |
| 81 return eval(env.create(), eval(env, args.head)); | |
| 82 } | |
| 83 | |
| 84 static _apply(Environment env, args) { | |
| 85 return eval(env, args.head)(env.create(), args.tail); | |
| 86 } | |
| 87 | |
| 88 static _let(Environment env, args) { | |
| 89 var inner = env.create(); | |
| 90 var binding = args.head; | |
| 91 while (binding != null) { | |
| 92 inner.define(binding.head.head, eval(env, binding.head.tail.head)); | |
| 93 binding = binding.tail; | |
| 94 } | |
| 95 return evalList(inner, args.tail); | |
| 96 } | |
| 97 | |
| 98 static _set(Environment env, args) { | |
| 99 return env[args.head] = eval(env, args.tail.head); | |
| 100 } | |
| 101 | |
| 102 static _print(Environment env, args) { | |
| 103 var buffer = new StringBuffer(); | |
| 104 while (args != null) { | |
| 105 buffer.write(eval(env, args.head)); | |
| 106 args = args.tail; | |
| 107 } | |
| 108 print(buffer); | |
| 109 return null; | |
| 110 } | |
| 111 | |
| 112 static _if(Environment env, args) { | |
| 113 var condition = eval(env, args.head); | |
| 114 if (condition) { | |
| 115 if (args.tail != null) { | |
| 116 return eval(env, args.tail.head); | |
| 117 } | |
| 118 } else { | |
| 119 if (args.tail != null && args.tail.tail != null) { | |
| 120 return eval(env, args.tail.tail.head); | |
| 121 } | |
| 122 } | |
| 123 return null; | |
| 124 } | |
| 125 | |
| 126 static _while(Environment env, args) { | |
| 127 var result = null; | |
| 128 while (eval(env, args.head)) { | |
| 129 result = evalList(env, args.tail); | |
| 130 } | |
| 131 return result; | |
| 132 } | |
| 133 | |
| 134 static _and(Environment env, args) { | |
| 135 while (args != null) { | |
| 136 if (!eval(env, args.head)) { | |
| 137 return false; | |
| 138 } | |
| 139 args = args.tail; | |
| 140 } | |
| 141 return true; | |
| 142 } | |
| 143 | |
| 144 static _or(Environment env, args) { | |
| 145 while (args != null) { | |
| 146 if (eval(env, args.head)) { | |
| 147 return true; | |
| 148 } | |
| 149 args = args.tail; | |
| 150 } | |
| 151 return false; | |
| 152 } | |
| 153 | |
| 154 static _not(Environment env, args) { | |
| 155 return !eval(env, args.head); | |
| 156 } | |
| 157 | |
| 158 static _plus(Environment env, args) { | |
| 159 var value = eval(env, args.head); | |
| 160 for (args = args.tail; args != null; args = args.tail) { | |
| 161 value += eval(env, args.head); | |
| 162 } | |
| 163 return value; | |
| 164 } | |
| 165 | |
| 166 static _minus(Environment env, args) { | |
| 167 var value = eval(env, args.head); | |
| 168 if (args.tail == null) { | |
| 169 return -value; | |
| 170 } | |
| 171 for (args = args.tail; args != null; args = args.tail) { | |
| 172 value -= eval(env, args.head); | |
| 173 } | |
| 174 return value; | |
| 175 } | |
| 176 | |
| 177 static _multiply(Environment env, args) { | |
| 178 var value = eval(env, args.head); | |
| 179 for (args = args.tail; args != null; args = args.tail) { | |
| 180 value *= eval(env, args.head); | |
| 181 } | |
| 182 return value; | |
| 183 } | |
| 184 | |
| 185 static _divide(Environment env, args) { | |
| 186 var value = eval(env, args.head); | |
| 187 for (args = args.tail; args != null; args = args.tail) { | |
| 188 value /= eval(env, args.head); | |
| 189 } | |
| 190 return value; | |
| 191 } | |
| 192 | |
| 193 static _modulo(Environment env, args) { | |
| 194 var value = eval(env, args.head); | |
| 195 for (args = args.tail; args != null; args = args.tail) { | |
| 196 value %= eval(env, args.head); | |
| 197 } | |
| 198 return value; | |
| 199 } | |
| 200 | |
| 201 static _smaller(Environment env, args) { | |
| 202 return eval(env, args.head) < eval(env, args.tail.head); | |
| 203 } | |
| 204 | |
| 205 static _smallerOrEqual(Environment env, args) { | |
| 206 return eval(env, args.head) <= eval(env, args.tail.head); | |
| 207 } | |
| 208 | |
| 209 static _equal(Environment env, args) { | |
| 210 return eval(env, args.head) == eval(env, args.tail.head); | |
| 211 } | |
| 212 | |
| 213 static _notEqual(Environment env, args) { | |
| 214 return eval(env, args.head) != eval(env, args.tail.head); | |
| 215 } | |
| 216 | |
| 217 static _larger(Environment env, args) { | |
| 218 return eval(env, args.head) > eval(env, args.tail.head); | |
| 219 } | |
| 220 | |
| 221 static _largerOrEqual(Environment env, args) { | |
| 222 return eval(env, args.head) >= eval(env, args.tail.head); | |
| 223 } | |
| 224 | |
| 225 static _cons(Environment env, args) { | |
| 226 return new Cons(eval(env, args.head), eval(env, args.tail.head)); | |
| 227 } | |
| 228 | |
| 229 static _car(Environment env, args) { | |
| 230 var cons = eval(env, args.head); | |
| 231 return cons is Cons ? cons.head : null; | |
| 232 } | |
| 233 | |
| 234 static _carSet(Environment env, args) { | |
| 235 var cons = eval(env, args.head); | |
| 236 if (cons is Cons) { | |
| 237 cons.head = eval(env, args.tail.head); | |
| 238 } | |
| 239 return cons; | |
| 240 } | |
| 241 | |
| 242 static _cdr(Environment env, args) { | |
| 243 var cons = eval(env, args.head); | |
| 244 return cons is Cons ? cons.tail : null; | |
| 245 } | |
| 246 | |
| 247 static _cdrSet(Environment env, args) { | |
| 248 var cons = eval(env, args.head); | |
| 249 if (cons is Cons) { | |
| 250 cons.tail = eval(env, args.tail.head); | |
| 251 } | |
| 252 return cons; | |
| 253 } | |
| 254 } | |
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Chromium Code Reviews
Issue 2989763002:
Update charted to 0.4.8 and roll (Closed)
