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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2002-2003, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
** $Id$
\* */
package scala;
/** The <code>Predef</code> object provides definitions that are
* accessible in all Scala compilation units without explicit
* qualification.
*/
object Predef {
// aliases -------------------------------------------------------
type byte = scala.Byte;
type short = scala.Short;
type char = scala.Char;
type int = scala.Int;
type long = scala.Long;
type float = scala.Float;
type double = scala.Double;
type boolean = scala.Boolean;
type unit = scala.Unit;
type String = java.lang.String;
type NullPointerException = java.lang.NullPointerException;
type Throwable = java.lang.Throwable;
type Pair[+p, +q] = Tuple2[p, q];
def Pair[a, b](x: a, y: b) = Tuple2(x, y);
type Triple[+a, +b, +c] = Tuple3[a, b, c];
def Triple[a, b, c](x: a, y: b, z: c) = Tuple3(x, y, z);
def id[a](x: a): a = x;
def fst[a](x: a, y: Any): a = x;
def scd[a](x: Any, y: a): a = y;
type Function[-a,+b] = Function1[a,b];
// arrays -----------------------------------------------------------
/** Create an array with given elements.
*
* @param xs the elements to put in the array
* @return the array containing elements xs.
*/
def Array[A](xs: A*): Array[A] = {
val array: Array[A] = new Array[A](xs.length);
var i = 0;
for (val x <- xs.elements) { array(i) = x; i = i + 1; }
array;
}
// errors and asserts -------------------------------------------------
def error(message: String): All = throw new Error(message);
def exit: Unit = java.lang.System.exit(0);
def assert(assertion: Boolean): Unit = {
if (!assertion)
throw new Error("assertion failed");
}
def assert(assertion: Boolean, message: Any): Unit = {
if (!assertion)
throw new Error("assertion failed: " + message);
}
// views -------------------------------------------------------------
def view(x: int): Ordered[int] = new Ordered[int] with Proxy(x) {
def compareTo [b >: int <% Ordered[b]](y: b): int = y match {
case y1: int =>
if (x < y1) -1
else if (x > y1) 1
else 0
case _ => -(y compareTo x)
}
}
def view(x: char): Ordered[char] = new Ordered[char] with Proxy(x) {
def compareTo [b >: char <% Ordered[b]](y: b): int = y match {
case y1: char =>
if (x < y1) -1
else if (x > y1) 1
else 0
case _ => -(y compareTo x)
}
}
def view(x: long): Ordered[long] = new Ordered[long] with Proxy(x) {
def compareTo [b >: long <% Ordered[b]](y: b): int = y match {
case y1: long =>
if (x < y1) -1
else if (x > y1) 1
else 0
case _ => -(y compareTo x)
}
}
def view(x: float): Ordered[float] = new Ordered[float] with Proxy(x) {
def compareTo [b >: float <% Ordered[b]](y: b): int = y match {
case y1: float =>
if (x < y1) -1
else if (x > y1) 1
else 0
case _ => -(y compareTo x)
}
}
def view(x: double): Ordered[double] = new Ordered[double] with Proxy(x) {
def compareTo [b >: double <% Ordered[b]](y: b): int = y match {
case y1: double =>
if (x < y1) -1
else if (x > y1) 1
else 0
case _ => -(y compareTo x)
}
}
def view(x: boolean): Ordered[boolean] = new Ordered[boolean] with Proxy(x) {
def compareTo [b >: boolean <% Ordered[b]](y: b): int = y match {
case y1: boolean =>
if (x == y1) 0
else if (x) 1
else -1
case _ => -(y compareTo x)
}
}
def view[A](xs: Array[A]): Seq[A] = new Seq[A] {
def length = xs.length;
def elements = Iterator.fromArray(xs);
def apply(n: Int) = xs(n);
override def hashCode(): Int = xs.hashCode();
override def equals(y: Any): Boolean = xs.equals(y);
override protected def stringPrefix: String = "Array";
}
def view[A <% Ordered[A]](xs: Array[A]): Ordered[Array[A]] = new Ordered[Array[A]] with Proxy(xs) {
def compareTo[B >: Array[A] <% Ordered[B]](that: B): Int = that match {
case ys: Array[A] =>
var i, res = 0;
while ((i < xs.length) && (i < ys.length) && (res == 0)) {
res = xs(i) compareTo ys(i);
i = i + 1;
}
if (res != 0) res
else if (i < xs.length) 1
else -1
case _ =>
-(that compareTo xs)
}
}
def view(x: String): Ordered[String] = new Ordered[String] with Proxy(x) {
def compareTo [b >: String <% Ordered[b]](y: b): int = y match {
case y1: String => x compareTo y1;
case _ => -(y compareTo x)
}
}
}
|
