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/* NSC -- new Scala compiler
* Copyright 2005-2009 LAMP/EPFL
* @author Burak Emir
*/
// $Id$
package scala.tools.nsc
package matching
import scala.tools.nsc.util.NoPosition
/**
* @author Burak Emir
*/
trait PatternNodes extends ast.TreeDSL
{
self: transform.ExplicitOuter =>
import global.{ typer => _, _ }
import CODE._
import definitions.{ ListClass, ConsClass }
object Types {
import definitions._
implicit def enrichType(x: Type): RichType = new RichType(x)
class RichType(undecodedTpe: Type) {
def tpe = decodedEqualsType(undecodedTpe)
def isAnyRef = tpe <:< AnyRefClass.tpe
// These tests for final classes can inspect the typeSymbol
private def is(s: Symbol) = tpe.typeSymbol eq s
def isByte = is(ByteClass)
def isShort = is(ShortClass)
def isInt = is(IntClass)
def isChar = is(CharClass)
def isBoolean = is(BooleanClass)
def isNothing = is(NothingClass)
def isArray = is(ArrayClass)
}
}
/** For folding a list into a well-typed x :: y :: etc :: tree. */
private def listFolder(tpe: Type) = {
val MethodType(_, TypeRef(pre, sym, _)) = ConsClass.primaryConstructor.tpe
val consRef = typeRef(pre, sym, List(tpe))
val listRef = typeRef(pre, ListClass, List(tpe))
def fold(x: Tree, xs: Tree) = unbind(x) match {
case _: Star => makeBind(definedVars(x), WILD(x.tpe))
case _ =>
val dummyMethod = new TermSymbol(NoSymbol, NoPosition, "matching$dummy")
val consType = MethodType(dummyMethod newSyntheticValueParams List(tpe, listRef), consRef)
Apply(TypeTree(consType), List(x, xs)) setType consRef
}
fold _
}
def normalizedListPattern(pats: List[Tree], tptArg: Type): Tree =
pats.foldRight(gen.mkNil)(listFolder(tptArg))
}
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