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import scala.util.parsing.combinator._
import scala.util.parsing.combinator.syntactical.StandardTokenParsers
import scala.util.parsing.input._
import scala.util.parsing.combinator.token._
import scala.collection.mutable.HashMap
object Test extends App{
import grammars2._
val head = phrase(exp)
println(extractResult(head(new lexical.Scanner("1"))))
println(extractResult(head(new lexical.Scanner("1+2"))))
println(extractResult(head(new lexical.Scanner("9*9"))))
println(extractResult(head(new lexical.Scanner("4*9+7"))))
println(extractResult(head(new lexical.Scanner("4*9+7*2+3*3"))))
println(extractResult(head(new lexical.Scanner("4*9+7*2+3*3+9*5+7*6*2"))))
println(extractResult(head(new lexical.Scanner("4*(9+7)*(2+3)*3"))))
}
object grammars2 extends StandardTokenParsers with PackratParsers{
def extractResult(r : ParseResult[_]) = r match{
case Success(a,_) => a
case NoSuccess(a,_) => a
}
lexical.delimiters ++= List("+","-","*","/","(",")")
lexical.reserved ++= List("Hello","World")
/*
* exp = sum | prod | num
* sum = exp ~ "+" ~ num
* prod = exp ~ "*" ~ num
*/
val exp : PackratParser[Int] = sum | prod | numericLit ^^{_.toInt} | "("~>exp<~")"
val sum : PackratParser[Int] = exp~("+"~>exp) ^^ {case x~y => x+y}
val prod: PackratParser[Int] = exp~("*"~>(numericLit ^^{_.toInt} | exp)) ^^ {case x~y => x*y}
/* lexical.reserved ++= List("a","b", "c")
val a : PackratParser[Any] = numericLit^^{x => primeFactors(x.toInt)}
val b : PackratParser[Any] = memo("b")
val c : PackratParser[Any] = memo("c")
val AnBnCn : PackratParser[Any] =
parseButDontEat(repMany1(a,b))~not(b)~>rep1(a)~repMany1(b,c)// ^^{case x~y => x:::y}
//val c : PackratParser[Any] = parseButDontEat(a)~a~a
//println(c((new PackratReader(new lexical.Scanner("45 24")))))
val r = new PackratReader(new lexical.Scanner("45 b c"))
println(AnBnCn(r))
println(r.getCache.size)
*/
}
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