negative steps supported

stdlib/src/jet/ByteRange.java

@@ -37,7 +37,10 @@ public final class ByteRange implements Range<Byte>, ByteIterable, JetObject {
     }
 
     public ByteIterator step(int step) {
-        return new MyIterator(start, count, step);
+        if(step < 0)
+            return new MyIterator(getEnd(), -count, -step);
+        else
+            return new MyIterator(start, count, step);
     }
 
     public ByteRange minus() {

stdlib/src/jet/CharRange.java

@@ -41,7 +41,10 @@ public final class CharRange implements Range<Character>, CharIterable, JetObjec
     }
 
     public CharIterator step(int step) {
-        return new MyIterator(start, count, step);
+        if(step < 0)
+            return new MyIterator(getEnd(), -count, -step);
+        else
+            return new MyIterator(start, count, step);
     }
 
     @Override

stdlib/src/jet/IntRange.java

@@ -21,7 +21,10 @@ public final class IntRange implements Range<Integer>, IntIterable, JetObject {
     }
 
     public IntIterator step(int step) {
-        return new MyIterator(start, count, step);
+        if(step < 0)
+            return new MyIterator(getEnd(), -count, -step);
+        else
+            return new MyIterator(start, count, step);
     }
 
     public boolean getIsReversed() {

stdlib/src/jet/LongRange.java

@@ -12,7 +12,10 @@ public final class LongRange implements Range<Long>, LongIterable, JetObject {
     }
 
     public LongIterator step(long step) {
-        return new MyIterator(start, count, step);
+        if(step < 0)
+            return new MyIterator(getEnd(), -count, -step);
+        else
+            return new MyIterator(start, count, step);
     }
 
     @Override

stdlib/src/jet/ShortRange.java

@@ -12,7 +12,10 @@ public final class ShortRange implements Range<Short>, ShortIterable, JetObject
     }
 
     public ShortIterator step(int step) {
-        return new MyIterator(start, count, step);
+        if(step < 0)
+            return new MyIterator(getEnd(), -count, -step);
+        else
+            return new MyIterator(start, count, step);
     }
 
     @Override