Implement interop iterable messages for ruby enumerables

Author: bjfish

spec/truffle/interop/iterator_spec.rb

@@ -10,17 +10,48 @@
 require_relative 'fixtures/classes'
 
 describe "Truffle::Interop iterator messages" do
-  it "allow to iterate an array" do
-    obj = [1, 2]
+  def should_have_iterator(obj, expected_values)
     Truffle::Interop.should.has_iterator?(obj)
+
     iterator = Truffle::Interop.iterator(obj)
     Truffle::Interop.should.iterator?(iterator)
-
-    Truffle::Interop.has_iterator_next_element?(iterator).should == true
-    Truffle::Interop.iterator_next_element(iterator).should == 1
-    Truffle::Interop.has_iterator_next_element?(iterator).should == true
-    Truffle::Interop.iterator_next_element(iterator).should == 2
+    expected_values.each do |value|
+      Truffle::Interop.has_iterator_next_element?(iterator).should == true
+      Truffle::Interop.iterator_next_element(iterator).should == value
+    end
     Truffle::Interop.has_iterator_next_element?(iterator).should == false
     -> { Truffle::Interop.iterator_next_element(iterator) }.should raise_error(StopIteration)
+
+    iterator = Truffle::Interop.iterator(obj)
+    Truffle::Interop.should.iterator?(iterator)
+    expected_values.each do |value|
+      Truffle::Interop.iterator_next_element(iterator).should == value
+    end
+    -> { Truffle::Interop.iterator_next_element(iterator) }.should raise_error(StopIteration)
+  end
+
+  it "allow to iterate an array" do
+    should_have_iterator([1, 2], [1, 2])
+  end
+
+  it "allows iterating a range" do
+    should_have_iterator(1..3, [1, 2, 3])
+  end
+
+  it "allows iterating a hash" do
+    should_have_iterator({ 1 => "one", 2 => "two"}, [[1, "one"], [2, "two"]])
+  end
+
+  it "allows iterating user defined classes" do
+    cls = Class.new do
+      include Enumerable
+      def each
+        yield 1
+        yield 2
+      end
+    end
+
+    obj = cls.new
+    should_have_iterator(obj, [1, 2])
   end
 end

src/main/java/org/truffleruby/core/CoreLibrary.java

@@ -175,6 +175,7 @@ public class CoreLibrary {
     public final RubyClass typeErrorClass;
     public final RubyClass zeroDivisionErrorClass;
     public final RubyModule enumerableModule;
+    public final RubyClass enumeratorClass;
     public final RubyModule errnoModule;
     public final RubyModule kernelModule;
     public final RubyModule truffleFFIModule;
@@ -194,6 +195,7 @@ public class CoreLibrary {
     public final RubyClass arityExceptionClass;
     public final RubyModule truffleFeatureLoaderModule;
     public final RubyModule truffleKernelOperationsModule;
+    public final RubyModule truffleInteropOperationsModule;
     public final RubyModule truffleStringOperationsModule;
     public final RubyModule truffleRegexpOperationsModule;
     public final RubyModule truffleRandomOperationsModule;
@@ -411,6 +413,7 @@ public CoreLibrary(RubyContext context, RubyLanguage language) {
         defineClass("Data"); // Needed by Socket::Ifaddr and defined in core MRI
         dirClass = defineClass("Dir");
         encodingClass = defineClass("Encoding");
+        enumeratorClass = defineClass("Enumerator");
         falseClass = defineClass("FalseClass");
         fiberClass = defineClass("Fiber");
         defineModule("FileTest");
@@ -516,6 +519,7 @@ public CoreLibrary(RubyContext context, RubyLanguage language) {
         defineModule(truffleModule, "System");
         truffleFeatureLoaderModule = defineModule(truffleModule, "FeatureLoader");
         truffleKernelOperationsModule = defineModule(truffleModule, "KernelOperations");
+        truffleInteropOperationsModule = defineModule(truffleModule, "InteropOperations");
         defineModule(truffleModule, "Binding");
         defineModule(truffleModule, "POSIX");
         defineModule(truffleModule, "Readline");
@@ -997,6 +1001,7 @@ public boolean isTruffleBootMainMethod(SharedMethodInfo info) {
             "/core/truffle/debug.rb",
             "/core/truffle/encoding_operations.rb",
             "/core/truffle/hash_operations.rb",
+            "/core/truffle/interop_operations.rb",
             "/core/truffle/numeric_operations.rb",
             "/core/truffle/proc_operations.rb",
             "/core/truffle/range_operations.rb",

src/main/java/org/truffleruby/language/RubyDynamicObject.java

@@ -9,6 +9,7 @@
  */
 package org.truffleruby.language;
 
+import com.oracle.truffle.api.interop.StopIterationException;
 import org.truffleruby.Layouts;
 import org.truffleruby.RubyContext;
 import org.truffleruby.RubyLanguage;
@@ -30,6 +31,7 @@
 import org.truffleruby.language.library.RubyLibrary;
 import org.truffleruby.language.library.RubyStringLibrary;
 import org.truffleruby.language.methods.GetMethodObjectNode;
+import org.truffleruby.language.objects.IsANode;
 import org.truffleruby.language.objects.LogicalClassNode;
 import org.truffleruby.language.objects.WriteObjectFieldNode;
 
@@ -285,6 +287,71 @@ public boolean isArrayElementRemovable(long index,
     }
     // endregion
 
+    // region Iterable Messages
+    @ExportMessage
+    public boolean hasIterator(
+            @CachedContext(RubyLanguage.class) RubyContext context,
+            @Exclusive @Cached IsANode isANode) {
+        return isANode.executeIsA(this, context.getCoreLibrary().enumerableModule);
+    }
+
+    @ExportMessage
+    public Object getIterator(
+            @CachedLibrary("this") InteropLibrary interopLibrary,
+            @CachedContext(RubyLanguage.class) RubyContext context,
+            @Exclusive @Cached DispatchNode dispatchNode) throws UnsupportedMessageException {
+        if (!interopLibrary.hasIterator(this)) {
+            throw UnsupportedMessageException.create();
+        }
+        return dispatchNode.call(context.getCoreLibrary().truffleInteropOperationsModule, "get_iterator", this);
+    }
+
+    @ExportMessage
+    public boolean isIterator(
+            @CachedContext(RubyLanguage.class) RubyContext context,
+            @Exclusive @Cached IsANode isANode) {
+        return isANode.executeIsA(this, context.getCoreLibrary().enumeratorClass);
+    }
+
+    @ExportMessage
+    public boolean hasIteratorNextElement(
+            @CachedLibrary("this") InteropLibrary interopLibrary,
+            @CachedContext(RubyLanguage.class) RubyContext context,
+            @Exclusive @Cached DispatchNode dispatchNode,
+            @Exclusive @Cached BooleanCastNode booleanCastNode) throws UnsupportedMessageException {
+        if (!interopLibrary.isIterator(this)) {
+            throw UnsupportedMessageException.create();
+        }
+        return booleanCastNode.executeToBoolean(
+                dispatchNode.call(
+                        context.getCoreLibrary().truffleInteropOperationsModule,
+                        "enumerator_has_next?",
+                        this));
+    }
+
+    @ExportMessage
+    public Object getIteratorNextElement(
+            @CachedLibrary("this") InteropLibrary interopLibrary,
+            @CachedContext(RubyLanguage.class) RubyContext context,
+            @Exclusive @Cached DispatchNode dispatchNode,
+            @Exclusive @Cached IsANode isANode,
+            @Exclusive @Cached ConditionProfile stopIterationProfile)
+            throws UnsupportedMessageException, StopIterationException {
+        if (!interopLibrary.isIterator(this)) {
+            throw UnsupportedMessageException.create();
+        }
+        try {
+            return dispatchNode.call(this, "next");
+        } catch (RaiseException e) {
+            if (stopIterationProfile
+                    .profile(isANode.executeIsA(e.getException(), context.getCoreLibrary().stopIterationClass))) {
+                throw StopIterationException.create(e);
+            }
+            throw e;
+        }
+    }
+    // endregion
+
     // region Pointer
     @ExportMessage
     public boolean isPointer(

src/main/ruby/truffleruby/core/truffle/interop_operations.rb

@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+# Copyright (c) 2021, 2021 Oracle and/or its affiliates. All rights reserved. This
+# code is released under a tri EPL/GPL/LGPL license. You can use it,
+# redistribute it and/or modify it under the terms of the:
+#
+# Eclipse Public License version 2.0, or
+# GNU General Public License version 2, or
+# GNU Lesser General Public License version 2.1.
+
+module Truffle
+  module InteropOperations
+    TO_ENUM = Kernel.instance_method(:to_enum)
+
+    def self.get_iterator(obj)
+      TO_ENUM.bind_call(obj, :each)
+    end
+
+    def self.enumerator_has_next?(enum)
+      begin
+        enum.peek
+        true
+      rescue StopIteration
+        false
+      end
+    end
+
+  end
+end