* enumerator.c: Fix state handling for Lazy#take

[bug #7696]

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

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38920 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

enumerator.c

@@ -105,7 +105,7 @@
 VALUE rb_cEnumerator;
 VALUE rb_cLazy;
 static ID id_rewind, id_each, id_new, id_initialize, id_yield, id_call, id_size;
-static ID id_eqq, id_next, id_result, id_lazy, id_receiver, id_arguments, id_method, id_force;
+static ID id_eqq, id_next, id_result, id_lazy, id_receiver, id_arguments, id_memo, id_method, id_force;
 static VALUE sym_each, sym_cycle;
 
 VALUE rb_eStopIteration;
@@ -1641,14 +1641,18 @@ lazy_zip(int argc, VALUE *argv, VALUE obj)
 static VALUE
 lazy_take_func(VALUE val, VALUE args, int argc, VALUE *argv)
 {
-    NODE *memo = RNODE(args);
+    long remain;
+    VALUE memo = rb_ivar_get(argv[0], id_memo);
+    if (NIL_P(memo)) {
+	memo = args;
+    }
 
     rb_funcall2(argv[0], id_yield, argc - 1, argv + 1);
-    if (--memo->u3.cnt == 0) {
+    if ((remain = NUM2LONG(memo)-1) == 0) {
-	memo->u3.cnt = memo->u2.argc;
 	return Qundef;
     }
     else {
+	rb_ivar_set(argv[0], id_memo, LONG2NUM(remain));
 	return Qnil;
     }
 }
@@ -1666,7 +1670,6 @@ lazy_take_size(VALUE lazy)
 static VALUE
 lazy_take(VALUE obj, VALUE n)
 {
-    NODE *memo;
     long len = NUM2LONG(n);
     int argc = 1;
     VALUE argv[3];
@@ -1680,9 +1683,8 @@ lazy_take(VALUE obj, VALUE n)
 	argv[2] = INT2NUM(0);
 	argc = 3;
     }
-    memo = NEW_MEMO(0, len, len);
     return lazy_set_method(rb_block_call(rb_cLazy, id_new, argc, argv,
-					 lazy_take_func, (VALUE) memo),
+					 lazy_take_func, n),
 			   rb_ary_new3(1, n), lazy_take_size);
 }
 
@@ -1955,6 +1957,7 @@ Init_Enumerator(void)
     id_eqq = rb_intern("===");
     id_receiver = rb_intern("receiver");
     id_arguments = rb_intern("arguments");
+    id_memo = rb_intern("memo");
     id_method = rb_intern("method");
     id_force = rb_intern("force");
     sym_each = ID2SYM(id_each);

test/ruby/test_lazy_enumerator.rb

@@ -243,6 +243,23 @@ class TestLazyEnumerator < Test::Unit::TestCase
     assert_equal((1..5).to_a, take5.force, bug6428)
   end
 
+  def test_take_nested
+    bug7696 = '[ruby-core:51470]'
+    a = Step.new(1..10)
+    take5 = a.lazy.take(5)
+    assert_equal([*(1..5)]*5, take5.flat_map{take5}.force, bug7696)
+  end
+
+  def test_take_rewound
+    bug7696 = '[ruby-core:51470]'
+    e=(1..42).lazy.take(2)
+    assert_equal 1, e.next
+    assert_equal 2, e.next
+    e.rewind
+    assert_equal 1, e.next
+    assert_equal 2, e.next
+  end
+
   def test_take_while
     a = Step.new(1..10)
     assert_equal(1, a.take_while {|i| i < 5}.first)