Generate specialized abstract iterators for unsigned types

generators/builtins/unsignedTypes.kt

@@ -21,6 +21,8 @@ fun generateUnsignedTypes(
         generate(File(targetDir, "kotlin/${type.capitalized}.kt")) { UnsignedTypeGenerator(type, it) }
     }
 
+    generate(File(targetDir, "kotlin/UIterators.kt"), ::UnsignedIteratorsGenerator)
+
 
 }
 
@@ -171,3 +173,23 @@ class UnsignedTypeGenerator(val type: UnsignedType, out: PrintWriter) : BuiltIns
     }
 
 }
+
+
+// TODO: reuse generator
+class UnsignedIteratorsGenerator(out: PrintWriter) : BuiltInsSourceGenerator(out) {
+    override fun getPackage() = "kotlin.collections"
+    override fun generateBody() {
+        for (type in UnsignedType.values()) {
+            val s = type.capitalized
+            out.println("/** An iterator over a sequence of values of type `$s`. */")
+            out.println("public abstract class ${s}Iterator : Iterator<$s> {")
+            // TODO: Sort modifiers
+            out.println("    override final fun next() = next$s()")
+            out.println()
+            out.println("    /** Returns the next value in the sequence without boxing. */")
+            out.println("    public abstract fun next$s(): $s")
+            out.println("}")
+            out.println()
+        }
+    }
+}

libraries/stdlib/unsigned/src/kotlin/UIterators.kt

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license 
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+// Auto-generated file. DO NOT EDIT!
+
+package kotlin.collections
+
+/** An iterator over a sequence of values of type `UByte`. */
+public abstract class UByteIterator : Iterator<UByte> {
+    override final fun next() = nextUByte()
+
+    /** Returns the next value in the sequence without boxing. */
+    public abstract fun nextUByte(): UByte
+}
+
+/** An iterator over a sequence of values of type `UShort`. */
+public abstract class UShortIterator : Iterator<UShort> {
+    override final fun next() = nextUShort()
+
+    /** Returns the next value in the sequence without boxing. */
+    public abstract fun nextUShort(): UShort
+}
+
+/** An iterator over a sequence of values of type `UInt`. */
+public abstract class UIntIterator : Iterator<UInt> {
+    override final fun next() = nextUInt()
+
+    /** Returns the next value in the sequence without boxing. */
+    public abstract fun nextUInt(): UInt
+}
+
+/** An iterator over a sequence of values of type `ULong`. */
+public abstract class ULongIterator : Iterator<ULong> {
+    override final fun next() = nextULong()
+
+    /** Returns the next value in the sequence without boxing. */
+    public abstract fun nextULong(): ULong
+}
+