* enumerator.c: Use to_enum for Enumerable methods returning Enumerators.

This makes Lazy#cycle no longer needed, so it was removed.
  Make Enumerator#chunk and slice_before return lazy Enumerators.
  [Bug #7715]

* internal.h: Remove ref to rb_enum_cycle_size; no longer needed

* enum.c: Make enum_cycle_size static.

* test/ruby/test_lazy_enumerator.rb: Test for above

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39058 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,17 @@
+Tue Feb  5 12:48:38 2013  Marc-Andre Lafortune  <ruby-core@marc-andre.ca>
+
+	* enumerator.c: Use to_enum for Enumerable methods returning
+	  Enumerators.
+	  This makes Lazy#cycle no longer needed, so it was removed.
+	  Make Enumerator#chunk and slice_before return lazy Enumerators.
+	  [Bug #7715]
+
+	* internal.h: Remove ref to rb_enum_cycle_size; no longer needed
+
+	* enum.c: Make enum_cycle_size static.
+
+	* test/ruby/test_lazy_enumerator.rb: Test for above
+
 Tue Feb  5 12:48:10 2013  Marc-Andre Lafortune  <ruby-core@marc-andre.ca>
 
 	* enumerator.c: Finalize and document Lazy.new. [Bug #7248]

enum.c

@@ -2238,9 +2238,8 @@ cycle_i(VALUE i, VALUE ary, int argc, VALUE *argv)
     return Qnil;
 }
 
-#define enum_cycle_size rb_enum_cycle_size
+static VALUE
-VALUE
+enum_cycle_size(VALUE self, VALUE args)
-rb_enum_cycle_size(VALUE self, VALUE args)
 {
     long mul;
     VALUE n = Qnil;

enumerator.c

@@ -463,7 +463,13 @@ lazy_to_enum_i(VALUE self, VALUE meth, int argc, VALUE *argv, VALUE (*size_fn)(A
 VALUE
 rb_enumeratorize_with_size(VALUE obj, VALUE meth, int argc, VALUE *argv, VALUE (*size_fn)(ANYARGS))
 {
-    return enumerator_init(enumerator_allocate(rb_cEnumerator), obj, meth, argc, argv, size_fn, Qnil);
+    /* Similar effect as calling obj.to_enum, i.e. dispatching to either
+       Kernel#to_enum vs Lazy#to_enum */
+    if (RTEST(rb_obj_is_kind_of(obj, rb_cLazy)))
+	return lazy_to_enum_i(obj, meth, argc, argv, size_fn);
+    else
+	return enumerator_init(enumerator_allocate(rb_cEnumerator),
+	    obj, meth, argc, argv, size_fn, Qnil);
 }
 
 static VALUE
@@ -1893,12 +1899,9 @@ lazy_drop_while(VALUE obj)
 }
 
 static VALUE
-lazy_cycle(int argc, VALUE *argv, VALUE obj)
+lazy_super(int argc, VALUE *argv, VALUE lazy)
 {
-    if (rb_block_given_p()) {
+    return enumerable_lazy(rb_call_super(argc, argv));
-	return rb_call_super(argc, argv);
-    }
-    return lazy_to_enum_i(obj, sym_cycle, argc, argv, rb_enum_cycle_size);
 }
 
 static VALUE
@@ -2005,8 +2008,9 @@ InitVM_Enumerator(void)
     rb_define_method(rb_cLazy, "take_while", lazy_take_while, 0);
     rb_define_method(rb_cLazy, "drop", lazy_drop, 1);
     rb_define_method(rb_cLazy, "drop_while", lazy_drop_while, 0);
-    rb_define_method(rb_cLazy, "cycle", lazy_cycle, -1);
     rb_define_method(rb_cLazy, "lazy", lazy_lazy, 0);
+    rb_define_method(rb_cLazy, "chunk", lazy_super, -1);
+    rb_define_method(rb_cLazy, "slice_before", lazy_super, -1);
 
     rb_define_alias(rb_cLazy, "force", "to_a");
 

internal.h

@@ -90,9 +90,6 @@ ID rb_id_encoding(void);
 /* encoding.c */
 void rb_gc_mark_encodings(void);
 
-/* enum.c */
-VALUE rb_enum_cycle_size(VALUE self, VALUE args);
-
 /* error.c */
 NORETURN(PRINTF_ARGS(void rb_compile_bug(const char*, int, const char*, ...), 3, 4));
 VALUE rb_check_backtrace(VALUE);

test/ruby/test_lazy_enumerator.rb

@@ -447,4 +447,20 @@ EOS
       assert_raise(ArgumentError){ [].lazy.send(method) }
     end
   end
+
+  def test_laziness_conservation
+    bug7507 = '[ruby-core:51510]'
+    {
+      slice_before: //,
+      with_index: nil,
+      cycle: nil,
+      each_with_object: 42,
+      each_slice: 42,
+      each_entry: nil,
+      each_cons: 42,
+    }.each do |method, arg|
+      assert_equal Enumerator::Lazy, [].lazy.send(method, *arg).class, bug7507
+    end
+    assert_equal Enumerator::Lazy, [].lazy.chunk{}.class, bug7507
+  end
 end