Maintenance of Predef.

1) Deprecates much of Predef and scala.Console, especially:

 - the read* methods (see below)
 - the set{Out,Err,In} methods (see SI-4793)

2) Removed long-deprecated:

 - Predef#exit
 - Predef#error should have gone, but could not due to sbt

At least the whole source base has now been future-proofed
against the eventual removal of Predef#error.

The low justification for the read* methods should be readily
apparent: they are little used and have no call to be in global
namespace, especially given their weird ad hoc semantics and
unreasonably tempting names such as readBoolean().

3) Segregated the deprecated elements in Predef from the part
which still thrives.

4) Converted all the standard Predef implicits into implicit
classes, value classes where possible:

  - ArrowAssoc, Ensuring, StringFormat, StringAdd, RichException (value)
  - SeqCharSequence, ArrayCharSequence (non-value)

Non-implicit deprecated stubs prop up the names of the
formerly converting methods.

1 files changed, 12 insertions, 12 deletions

diff --git a/test/files/run/Course-2002-07.scala b/test/files/run/Course-2002-07.scala
index 7848ae3e8e..055ff74d81 100644
--- a/test/files/run/Course-2002-07.scala
+++ b/test/files/run/Course-2002-07.scala
@@ -16,13 +16,13 @@ object M0 {
     def isNumber: Boolean = true;
     def isSum: Boolean = false;
     def numValue: Int = n;
-    def leftOp: Expr = error("Number.leftOp");
-    def rightOp: Expr = error("Number.rightOp");
+    def leftOp: Expr = sys.error("Number.leftOp");
+    def rightOp: Expr = sys.error("Number.rightOp");
   }
   class Sum(e1: Expr, e2: Expr) extends Expr {
     def isNumber: Boolean = false;
     def isSum: Boolean = true;
-    def numValue: Int = error("Sum.numValue");
+    def numValue: Int = sys.error("Sum.numValue");
     def leftOp: Expr = e1;
     def rightOp: Expr = e2;
   }
@@ -30,7 +30,7 @@ object M0 {
   class Prod(e1: Expr, e2: Expr) extends Expr {
     def isNumber: Boolean = false;
     def isSum: Boolean = false;
-    def numValue: Int = error("Prod.numValue");
+    def numValue: Int = sys.error("Prod.numValue");
     def leftOp: Expr = e1;
     def rightOp: Expr = e2;
   }
@@ -38,15 +38,15 @@ object M0 {
   class Var(x: String) extends Expr {
     def isNumber: Boolean = false;
     def isSum: Boolean = false;
-    def numValue: Int = error("Var.numValue");
-    def leftOp: Expr = error("Var.leftOp");
-    def rightOp: Expr = error("Var.rightOp");
+    def numValue: Int = sys.error("Var.numValue");
+    def leftOp: Expr = sys.error("Var.leftOp");
+    def rightOp: Expr = sys.error("Var.rightOp");
   }
 
   def eval(e: Expr): Int = {
     if (e.isNumber) e.numValue
     else if (e.isSum) eval(e.leftOp) + eval(e.rightOp)
-    else error("unknown expression")
+    else sys.error("unknown expression")
   }
 
   def test = {
@@ -375,7 +375,7 @@ object M9 {
 object MA {
 
   def lookup[k,v](xs: List[Pair[k,v]], k: k): v = xs match {
-    case List() => error("no value for " + k)
+    case List() => sys.error("no value for " + k)
     case Pair(k1,v1) :: xs1 => if (k1 == k) v1 else lookup(xs1, k)
   }
 
@@ -410,7 +410,7 @@ object MA {
 
   def eval(e: Expr): Int = e match {
     case Number(n) => n
-    case Var(_) => error("cannot evaluate variable")
+    case Var(_) => sys.error("cannot evaluate variable")
     case Sum(e1, e2) => eval(e1) + eval(e2)
     case Prod(e1, e2) => eval(e1) * eval(e2)
   }
@@ -453,7 +453,7 @@ object Utils {
     if (y == 1) x else if (y % 2 == 0) power0(x*x,y/2) else x*power0(x, y-1);
 
   def power(x: Int, y: Int): Int = (x,y) match {
-    case Pair(0,0) => error("power(0,0)")
+    case Pair(0,0) => sys.error("power(0,0)")
     case Pair(0,_) => 0
     case Pair(1,_) => 1
     case Pair(_,0) => 1
@@ -463,7 +463,7 @@ object Utils {
   }
 
   def lookup(entries: List[(String,Int)], key: String): Int = entries match {
-    case List()                       => error("no value for " + key)
+    case List()                       => sys.error("no value for " + key)
     case Pair(k,v) :: _ if (k == key) => v
     case _ :: rest                    => lookup(rest, key)
   }