KT-729 Need to support arrays as varargs

runtime/src/jet/runtime/Intrinsics.java

@@ -19,6 +19,8 @@ package jet.runtime;
 import jet.Function0;
 
 import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Iterator;
 
 /**
  * @author alex.tkachman
@@ -82,4 +84,36 @@ public class Intrinsics {
             return sanitizeStackTrace(this);
         }
     }
+
+    public static class SpreadBuilder extends ArrayList {
+        public void addSpread(Object array) {
+            if(array != null) {
+                if(array instanceof Object[]) {
+                    Object[] arr = (Object[]) array;
+                    if(arr.length > 0) {
+                        ensureCapacity(size() + arr.length);
+                        for (int i = 0; i < arr.length; i++) {
+                            add(arr[i]);
+                        }
+                    }
+                }
+                else if(array instanceof Collection) {
+                    addAll((Collection) array);
+                }
+                else if(array instanceof Iterable) {
+                    for(Iterator iterator = ((Iterable) array).iterator(); iterator.hasNext(); ) {
+                        add(iterator.next());
+                    }
+                }
+                else if(array instanceof Iterator) {
+                    for(Iterator iterator = ((Iterator) array); iterator.hasNext(); ) {
+                        add(iterator.next());
+                    }
+                }
+                else {
+                    throw new UnsupportedOperationException("Don't know how to spread " + array.getClass());
+                }
+            }
+        }
+    }
 }