extension function for converting a list of elements

src/org/jetbrains/jet/j2k/ast/Block.kt

@@ -11,7 +11,7 @@ public open class Block(val statements: List<Statement>, val notEmpty: Boolean =
 
     public override fun toKotlin(): String {
         if (!isEmpty()) {
-            return "{\n" + AstUtil.joinNodes(statements, "\n") + "\n}"
+            return "{\n" + statements.toKotlin("\n") + "\n}"
         }
 
         return ""

src/org/jetbrains/jet/j2k/ast/Util.kt

@@ -0,0 +1,12 @@
+package org.jetbrains.jet.j2k.ast
+
+import java.util.List
+
+fun List<out Node>.toKotlin(separator: String): String {
+    val result = StringBuilder()
+    for(x in this) {
+        if (result.length() > 0) result.append(separator)
+        result.append(x.toKotlin())
+    }
+    return result.toString()!!
+}