113   case c::s => ders(s, der(c, r))

   113   case c::s => ders(s, der(c, r))

   114 }

   114 }

   115 

   115 

   116 

   116 

   117 // regular expressions for the While language

   117 // regular expressions for the While language

   120 val ID = SYM ~ (SYM | DIGIT).% 

   120 val ID = SYM ~ (SYM | DIGIT).% 

   121 val NUM = PLUS(DIGIT)

   121 val NUM = PLUS(DIGIT)

   122 val KEYWORD : Rexp = "if" | "then" | "else" | "write" | "def"

   122 val KEYWORD : Rexp = "if" | "then" | "else" | "write" | "def"

   123 val SEMI: Rexp = ";"

   123 val SEMI: Rexp = ";"

   124 val COMMA: Rexp = ","

   124 val COMMA: Rexp = ","

   443   }

   443   }

   444 }

   444 }

   445 

   445 

   446 def compile(class_name: String, input: String) : String = {

   446 def compile(class_name: String, input: String) : String = {

   447   val tks = tokenizer(input)

   447   val tks = tokenizer(input)

   449   val ast = Prog.parse_single(tks)

   449   val ast = Prog.parse_single(tks)

   450   val instructions = ast.flatMap(compile_decl).mkString

   450   val instructions = ast.flatMap(compile_decl).mkString

   451   (library + instructions).replaceAllLiterally("XXX", class_name)

   451   (library + instructions).replaceAllLiterally("XXX", class_name)

   452 }

   452 }

   453 

   455 

   454 

   456 

   455 def compile_file(file_name: String) = {

   457 def compile_file(file_name: String) = {

   456   val class_name = file_name.split('.')(0)

   458   val class_name = file_name.split('.')(0)

   457   val output = compile(class_name, fromFile(file_name))

   459   val output = compile(class_name, fromFile(file_name))

   474   println("Time: " + time_needed(2, ("java " + class_name + "/" + class_name).!))

   476   println("Time: " + time_needed(2, ("java " + class_name + "/" + class_name).!))

   475 }

   477 }

   476 

   478 

   477 

   479 

   478 //examples

   480 //examples

   480 //compile_run("fact.rec")

   483 //compile_run("fact.rec")