From 19c3aa9b31d9253b73469b3aad50112bd4084a68 Mon Sep 17 00:00:00 2001
From: Paul Phillips <paulp@improving.org>
Date: Tue, 30 Jun 2009 13:26:06 +0000
Subject: A few residual DSL bits.

---
 src/compiler/scala/tools/nsc/ast/TreeDSL.scala     | 13 ++++++---
 .../scala/tools/nsc/ast/parser/TreeBuilder.scala   | 31 ++++++++--------------
 2 files changed, 21 insertions(+), 23 deletions(-)

diff --git a/src/compiler/scala/tools/nsc/ast/TreeDSL.scala b/src/compiler/scala/tools/nsc/ast/TreeDSL.scala
index e54bdab529..52c39e6ada 100644
--- a/src/compiler/scala/tools/nsc/ast/TreeDSL.scala
+++ b/src/compiler/scala/tools/nsc/ast/TreeDSL.scala
@@ -38,9 +38,16 @@ trait TreeDSL {
     def UNIT          = LIT(())
     val ZERO          = LIT(0)
 
-    def WILD(tpe: Type = null) =
-      if (tpe == null) Ident(nme.WILDCARD)
-      else Ident(nme.WILDCARD) setType tpe
+    object WILD {
+      def apply(tpe: Type = null) =
+        if (tpe == null) Ident(nme.WILDCARD)
+        else Ident(nme.WILDCARD) setType tpe
+
+      def unapply(other: Any) = other match {
+        case Ident(nme.WILDCARD)  => true
+        case _                    => false
+      }
+    }
 
     def fn(lhs: Tree, op:   Name, args: Tree*)  = Apply(Select(lhs, op), args.toList)
     def fn(lhs: Tree, op: Symbol, args: Tree*)  = Apply(Select(lhs, op), args.toList)
diff --git a/src/compiler/scala/tools/nsc/ast/parser/TreeBuilder.scala b/src/compiler/scala/tools/nsc/ast/parser/TreeBuilder.scala
index a1949cc424..5f1030d9f9 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/TreeBuilder.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/TreeBuilder.scala
@@ -34,14 +34,14 @@ abstract class TreeBuilder extends TreeDSL
   private object patvarTransformer extends Transformer {
     override def transform(tree: Tree): Tree = tree match {
       case Ident(name) if (treeInfo.isVarPattern(tree) && name != nme.WILDCARD) =>
-        atPos(tree.pos)(Bind(name, atPos(tree) (Ident(nme.WILDCARD))))
+        atPos(tree.pos)(Bind(name, atPos(tree)(WILD())))
       case Typed(id @ Ident(name), tpt) if (treeInfo.isVarPattern(id) && name != nme.WILDCARD) =>
         atPos(tree.pos.withPoint(id.pos.point)) {
           Bind(name, atPos(tree.pos.withStart(tree.pos.point)) {
             // XXX question: how do these differ:
             // Typed(Ident(nme.WILDCARD), tpt) // annotation (eliminated by explicitouter)
             // Ident(nme.WILDCARD) setType tpt //
-            Typed(Ident(nme.WILDCARD), tpt)
+            Typed(WILD(), tpt)
           })
         }
       case Apply(fn @ Apply(_, _), args) =>
@@ -168,27 +168,20 @@ abstract class TreeBuilder extends TreeDSL
   /** A type tree corresponding to (possibly unary) intersection type */
   def makeIntersectionTypeTree(tps: List[Tree]): Tree =
     if (tps.tail.isEmpty) tps.head
-    else CompoundTypeTree(Template(tps, emptyValDef, List()))
+    else CompoundTypeTree(Template(tps, emptyValDef, Nil))
 
   /** Create tree representing a while loop */
-  def makeWhile(lname: Name, cond: Tree, body: Tree): Tree = {
-    val continu = Ident(lname) APPLY ()
-    val rhs     = IF (cond) THEN BLOCK(body, continu) ELSE UNIT
-
-    LabelDef(lname, Nil, rhs)
-  }
+  def makeWhile(lname: Name, cond: Tree, body: Tree): Tree =
+    LabelDef(lname, Nil, IF (cond) THEN BLOCK(body, Ident(lname) APPLY ()) ELSE UNIT)
 
   /** Create tree representing a do-while loop */
-  def makeDoWhile(lname: Name, body: Tree, cond: Tree): Tree = {
-    val continu = Apply(Ident(lname), List())
-    val rhs = Block(List(body), If(cond, continu, Literal(())))
-    LabelDef(lname, Nil, rhs)
-  }
+  def makeDoWhile(lname: Name, body: Tree, cond: Tree): Tree =
+    LabelDef(lname, Nil, BLOCK(body, IF (cond) THEN (Ident(lname) APPLY ()) ELSE UNIT))
 
   /** Create block of statements `stats'  */
   def makeBlock(stats: List[Tree]): Tree =
-    if (stats.isEmpty) Literal(())
-    else if (!stats.last.isTerm) Block(stats, Literal(()))
+    if (stats.isEmpty) UNIT
+    else if (!stats.last.isTerm) Block(stats, UNIT)
     else if (stats.length == 1) stats.head
     else Block(stats.init, stats.last)
 
@@ -206,9 +199,7 @@ abstract class TreeBuilder extends TreeDSL
               Select(rhs, nme.filter),
               List(
                 makeVisitor(
-                  List(
-                    CaseDef(pat1.syntheticDuplicate, EmptyTree, TRUE),
-                    CaseDef(Ident(nme.WILDCARD), EmptyTree, FALSE)),
+                  List(CASE(pat1.syntheticDuplicate) ==> TRUE, DEFAULT ==> FALSE),
                   false,
                   nme.CHECK_IF_REFUTABLE_STRING
                 )))
@@ -221,7 +212,7 @@ abstract class TreeBuilder extends TreeDSL
     ValDef(Modifiers(PARAM | SYNTHETIC), pname, TypeTree(), EmptyTree)
 
   def makeSyntheticTypeParam(pname: Name, bounds: Tree) =
-    TypeDef(Modifiers(DEFERRED | SYNTHETIC), pname, List(), bounds)
+    TypeDef(Modifiers(DEFERRED | SYNTHETIC), pname, Nil, bounds)
 
   abstract class Enumerator { def pos: Position }
   case class ValFrom(pos: Position, pat: Tree, rhs: Tree) extends Enumerator
-- 
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