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1 // A Small Compiler for a Simple Functional Language |
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2 // (includes an external lexer and parser) |
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3 // |
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4 // call with |
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5 // |
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6 // scala fun.scala fact |
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7 // |
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8 // scala fun.scala defs |
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9 // |
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10 // this will generate a .j file and run the jasmin |
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11 // assembler (installed at jvm/jasmin-2.4/jasmin.jar) |
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12 // it runs the resulting JVM file twice for timing |
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13 // purposes. |
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14 |
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15 |
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16 |
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17 |
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18 object Compiler { |
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19 |
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20 import java.io._ |
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21 import scala.util._ |
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22 import scala.sys.process._ |
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23 |
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24 // Abstract syntax trees for the Fun language |
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25 abstract class Exp extends Serializable |
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26 abstract class BExp extends Serializable |
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27 abstract class Decl extends Serializable |
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28 |
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29 case class Def(name: String, args: List[String], body: Exp) extends Decl |
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30 case class Main(e: Exp) extends Decl |
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31 |
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32 case class Call(name: String, args: List[Exp]) extends Exp |
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33 case class If(a: BExp, e1: Exp, e2: Exp) extends Exp |
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34 case class Write(e: Exp) extends Exp |
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35 case class Var(s: String) extends Exp |
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36 case class Num(i: Int) extends Exp |
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37 case class Aop(o: String, a1: Exp, a2: Exp) extends Exp |
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38 case class Sequence(e1: Exp, e2: Exp) extends Exp |
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39 case class Bop(o: String, a1: Exp, a2: Exp) extends BExp |
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40 |
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41 |
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42 // compiler - built-in functions |
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43 // copied from http://www.ceng.metu.edu.tr/courses/ceng444/link/jvm-cpm.html |
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44 // |
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45 |
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46 val library = """ |
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47 .class public XXX.XXX |
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48 .super java/lang/Object |
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49 |
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50 .method public static write(I)V |
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51 .limit locals 1 |
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52 .limit stack 2 |
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53 getstatic java/lang/System/out Ljava/io/PrintStream; |
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54 iload 0 |
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55 invokevirtual java/io/PrintStream/println(I)V |
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56 return |
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57 .end method |
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58 |
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59 """ |
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60 |
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61 // calculating the maximal needed stack size |
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62 def max_stack_exp(e: Exp): Int = e match { |
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63 case Call(_, args) => args.map(max_stack_exp).sum |
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64 case If(a, e1, e2) => max_stack_bexp(a) + (List(max_stack_exp(e1), max_stack_exp(e2)).max) |
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65 case Write(e) => max_stack_exp(e) + 1 |
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66 case Var(_) => 1 |
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67 case Num(_) => 1 |
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68 case Aop(_, a1, a2) => max_stack_exp(a1) + max_stack_exp(a2) |
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69 case Sequence(e1, e2) => List(max_stack_exp(e1), max_stack_exp(e2)).max |
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70 } |
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71 |
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72 def max_stack_bexp(e: BExp): Int = e match { |
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73 case Bop(_, a1, a2) => max_stack_exp(a1) + max_stack_exp(a2) |
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74 } |
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75 |
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76 |
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77 // for generating new labels |
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78 var counter = -1 |
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79 |
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80 def Fresh(x: String) = { |
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81 counter += 1 |
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82 x ++ "_" ++ counter.toString() |
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83 } |
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84 |
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85 // convenient string interpolations |
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86 // for instructions, labels and methods |
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87 import scala.language.implicitConversions |
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88 import scala.language.reflectiveCalls |
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89 |
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90 implicit def sring_inters(sc: StringContext) = new { |
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91 def i(args: Any*): String = " " ++ sc.s(args:_*) ++ "\n" |
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92 def l(args: Any*): String = sc.s(args:_*) ++ ":\n" |
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93 def m(args: Any*): String = sc.s(args:_*) ++ "\n" |
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94 } |
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95 |
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96 |
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97 type Env = Map[String, Int] |
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98 |
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99 // compile expressions |
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100 def compile_exp(a: Exp, env : Env) : String = a match { |
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101 case Num(i) => i"ldc $i" |
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102 case Var(s) => i"iload ${env(s)}" |
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103 case Aop("+", a1, a2) => compile_exp(a1, env) ++ compile_exp(a2, env) ++ i"iadd" |
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104 case Aop("-", a1, a2) => compile_exp(a1, env) ++ compile_exp(a2, env) ++ i"isub" |
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105 case Aop("*", a1, a2) => compile_exp(a1, env) ++ compile_exp(a2, env) ++ i"imul" |
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106 case Aop("/", a1, a2) => compile_exp(a1, env) ++ compile_exp(a2, env) ++ i"idiv" |
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107 case Aop("%", a1, a2) => compile_exp(a1, env) ++ compile_exp(a2, env) ++ i"irem" |
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108 case If(b, a1, a2) => { |
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109 val if_else = Fresh("If_else") |
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110 val if_end = Fresh("If_end") |
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111 compile_bexp(b, env, if_else) ++ |
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112 compile_exp(a1, env) ++ |
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113 i"goto $if_end" ++ |
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114 l"$if_else" ++ |
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115 compile_exp(a2, env) ++ |
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116 l"$if_end" |
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117 } |
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118 case Call(name, args) => { |
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119 val is = "I" * args.length |
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120 args.map(a => compile_exp(a, env)).mkString ++ |
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121 i"invokestatic XXX/XXX/$name($is)I" |
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122 } |
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123 case Sequence(a1, a2) => { |
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124 compile_exp(a1, env) ++ i"pop" ++ compile_exp(a2, env) |
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125 } |
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126 case Write(a1) => { |
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127 compile_exp(a1, env) ++ |
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128 i"dup" ++ |
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129 i"invokestatic XXX/XXX/write(I)V" |
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130 } |
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131 } |
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132 |
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133 // compile boolean expressions |
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134 def compile_bexp(b: BExp, env : Env, jmp: String) : String = b match { |
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135 case Bop("==", a1, a2) => |
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136 compile_exp(a1, env) ++ compile_exp(a2, env) ++ i"if_icmpne $jmp" |
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137 case Bop("!=", a1, a2) => |
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138 compile_exp(a1, env) ++ compile_exp(a2, env) ++ i"if_icmpeq $jmp" |
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139 case Bop("<", a1, a2) => |
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140 compile_exp(a1, env) ++ compile_exp(a2, env) ++ i"if_icmpge $jmp" |
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141 case Bop("<=", a1, a2) => |
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142 compile_exp(a1, env) ++ compile_exp(a2, env) ++ i"if_icmpgt $jmp" |
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143 } |
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144 |
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145 // compile function for declarations and main |
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146 def compile_decl(d: Decl) : String = d match { |
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147 case Def(name, args, a) => { |
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148 val env = args.zipWithIndex.toMap |
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149 val is = "I" * args.length |
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150 m".method public static $name($is)I" ++ |
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151 m".limit locals ${args.length}" ++ |
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152 m".limit stack ${1 + max_stack_exp(a)}" ++ |
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153 l"${name}_Start" ++ |
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154 compile_exp(a, env) ++ |
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155 i"ireturn" ++ |
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156 m".end method\n" |
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157 } |
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158 case Main(a) => { |
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159 m".method public static main([Ljava/lang/String;)V" ++ |
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160 m".limit locals 200" ++ |
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161 m".limit stack 200" ++ |
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162 compile_exp(a, Map()) ++ |
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163 i"invokestatic XXX/XXX/write(I)V" ++ |
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164 i"return" ++ |
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165 m".end method\n" |
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166 } |
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167 } |
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168 |
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169 // main compiler functions |
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170 |
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171 def time_needed[T](i: Int, code: => T) = { |
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172 val start = System.nanoTime() |
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173 for (j <- 1 to i) code |
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174 val end = System.nanoTime() |
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175 (end - start)/(i * 1.0e9) |
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176 } |
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177 |
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178 def deserialise[T](fname: String) : Try[T] = { |
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179 import scala.util.Using |
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180 Using(new ObjectInputStream(new FileInputStream(fname))) { |
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181 in => in.readObject.asInstanceOf[T] |
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182 } |
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183 } |
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184 |
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185 def compile(class_name: String) : String = { |
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186 val ast = deserialise[List[Decl]](class_name ++ ".prs").getOrElse(Nil) |
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187 val instructions = ast.map(compile_decl).mkString |
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188 (library + instructions).replaceAllLiterally("XXX", class_name) |
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189 } |
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190 |
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191 def compile_to_file(class_name: String) = { |
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192 val output = compile(class_name) |
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193 scala.tools.nsc.io.File(s"${class_name}.j").writeAll(output) |
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194 } |
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195 |
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196 def compile_and_run(class_name: String) : Unit = { |
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197 compile_to_file(class_name) |
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198 (s"java -jar jvm/jasmin-2.4/jasmin.jar ${class_name}.j").!! |
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199 println("Time: " + time_needed(1, (s"java ${class_name}/${class_name}").!)) |
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200 } |
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201 |
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202 |
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203 // some examples of .fun files |
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204 //compile_to_file("fact") |
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205 //compile_and_run("fact") |
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206 //compile_and_run("defs") |
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207 |
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208 |
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209 def main(args: Array[String]) : Unit = |
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210 compile_and_run(args(0)) |
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211 |
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212 |
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213 } |