added conversion from methods to functions usin...

added conversion from methods to functions using prefix operator `&'

2 files changed, 22 insertions, 4 deletions

diff --git a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
index 1cff3732f9..5ad34ef612 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
@@ -313,6 +313,7 @@ trait Parsers requires SyntaxAnalyzer {
     final val PLUS : Name = "+";
     final val BANG : Name = "!";
     final val TILDE: Name = "~";
+    final val AMP  : Name = "&";
     final val STAR : Name = "*";
     final val BAR  : Name = "|";
     final val OPT  : Name = "?";
@@ -768,7 +769,7 @@ trait Parsers requires SyntaxAnalyzer {
       reduceStack(true, base, top, 0, true)
     }
 
-    /** PrefixExpr   ::= [`-' | `+' | `~' | `!'] SimpleExpr
+    /** PrefixExpr   ::= [`-' | `+' | `~' | `!' | `&'] SimpleExpr
     */
     def prefixExpr(): Tree =
       if (in.token == IDENTIFIER && in.name == MINUS) {
@@ -781,6 +782,10 @@ trait Parsers requires SyntaxAnalyzer {
 	val pos = in.currentPos;
 	val name = ident();
 	atPos(pos) { Select(simpleExpr(), name) }
+      } else if (in.token == IDENTIFIER && in.name == AMP) {
+	val pos = in.currentPos;
+	val name = ident();
+	atPos(pos) { Typed(simpleExpr(), Function(List(), EmptyTree)) }
       } else {
 	simpleExpr()
       }
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index d556609f6b..680de70cf9 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -3,7 +3,7 @@
  * @author  Martin Odersky
  */
 // $Id$
-//todo: rewrite or disallow new T where T is a mixin (currently: <init> not a member of T)
+//todo: rewrite or disllow new T where T is a mixin (currently: <init> not a member of T)
 package scala.tools.nsc.typechecker
 
 import symtab.Flags._
@@ -23,7 +23,7 @@ trait Typers requires Analyzer {
   var implcnt = 0
   var impltime = 0l
 
-  final val xviews = false
+  final val xviews = true
 
   private val transformed = new HashMap[Tree, Tree]
 
@@ -386,7 +386,9 @@ trait Typers requires Analyzer {
             if (settings.migrate.value && !tree.symbol.isConstructor && isCompatible(mt, pt))
               error(tree.pos, migrateMsg + " method can be converted to function only if an expected function type is given");
             else
-              error(tree.pos, "missing arguments for "+tree.symbol+tree.symbol.locationString)
+              error(tree.pos, "missing arguments for "+tree.symbol+tree.symbol.locationString+
+                    if (tree.symbol.isConstructor) ""
+                    else ";\nprefix this method with `&' if you want to treat it as a partially applied function")
           }
           setError(tree)
         }
@@ -1431,6 +1433,17 @@ trait Typers requires Analyzer {
             error(tree.pos, ""+tpt1.tpe.symbol+" is abstract; cannot be instantiated")
           copy.New(tree, tpt1).setType(tpt1.tpe)
 
+        case Typed(expr, Function(List(), EmptyTree)) =>
+          val expr1 = typed1(expr, mode, pt);
+          expr1.tpe match {
+            case MethodType(formals, _) =>
+              adapt(expr1, mode, functionType(formals map (t => WildcardType), WildcardType))
+            case ErrorType =>
+              expr1
+            case _ =>
+              errorTree(expr1, "`&' must be applied to method type; cannot be applied to " + expr1.tpe)
+          }
+
         case Typed(expr, tpt @ Ident(name)) if (name == nme.WILDCARD_STAR.toTypeName) =>
           val expr1 = typed(expr, mode & stickyModes, seqType(pt))
           expr1.tpe.baseType(SeqClass) match {