From 2c7cf9410ac858dcffdc9943fa0cff781c654624 Mon Sep 17 00:00:00 2001
From: Edward Diener <eldiener@tropicsoft.com>
Date: Mon, 28 Apr 2014 22:12:08 -0400
Subject: [PATCH] Added variadic version of BOOST_PP_EMPTY and added new
 is_empty tests.

---
 .../boost/preprocessor/facilities/empty.hpp   |  7 ++++
 .../facilities/is_empty_variadic.hpp          |  6 +--
 test/isempty.cxx                              | 40 ++++++++++++++++---
 3 files changed, 45 insertions(+), 8 deletions(-)

diff --git a/include/boost/preprocessor/facilities/empty.hpp b/include/boost/preprocessor/facilities/empty.hpp
index 46db190..99e1daa 100644
--- a/include/boost/preprocessor/facilities/empty.hpp
+++ b/include/boost/preprocessor/facilities/empty.hpp
@@ -8,14 +8,21 @@
 #  */
 #
 # /* Revised by Paul Mensonides (2002) */
+# /* Revised by Edward Diener (2014) */
 #
 # /* See http://www.boost.org for most recent version. */
 #
 # ifndef BOOST_PREPROCESSOR_FACILITIES_EMPTY_HPP
 # define BOOST_PREPROCESSOR_FACILITIES_EMPTY_HPP
 #
+# include <boost/preprocessor/config/config.hpp>
+#
 # /* BOOST_PP_EMPTY */
 #
+# if BOOST_PP_VARIADICS
+# define BOOST_PP_EMPTY(...)
+# else
 # define BOOST_PP_EMPTY()
+# endif
 #
 # endif
diff --git a/include/boost/preprocessor/facilities/is_empty_variadic.hpp b/include/boost/preprocessor/facilities/is_empty_variadic.hpp
index 27b4ec0..c2700fe 100644
--- a/include/boost/preprocessor/facilities/is_empty_variadic.hpp
+++ b/include/boost/preprocessor/facilities/is_empty_variadic.hpp
@@ -16,10 +16,10 @@
 #
 # if BOOST_PP_VARIADICS
 #
+# include <boost/preprocessor/facilities/empty.hpp>
 # include <boost/preprocessor/punctuation/is_begin_parens.hpp>
 # include <boost/preprocessor/facilities/detail/is_empty.hpp>
 #
-#define BOOST_PP_IS_EMPTY_GEN_ZERO(...) 0
 #if BOOST_PP_VARIADICS_MSVC && _MSC_VER <= 1400
 #
 #define BOOST_PP_IS_EMPTY(param) \
@@ -31,7 +31,7 @@
         ) \
       ) \
       ( \
-      BOOST_PP_IS_EMPTY_GEN_ZERO, \
+      0 BOOST_PP_EMPTY, \
       BOOST_PP_DETAIL_IS_EMPTY_PROCESS \
       ) \
     (param) \
@@ -46,7 +46,7 @@
         ) \
       ) \
       ( \
-      BOOST_PP_IS_EMPTY_GEN_ZERO, \
+      0 BOOST_PP_EMPTY, \
       BOOST_PP_DETAIL_IS_EMPTY_PROCESS \
       ) \
     (__VA_ARGS__) \
diff --git a/test/isempty.cxx b/test/isempty.cxx
index f2d7bc2..94be43a 100644
--- a/test/isempty.cxx
+++ b/test/isempty.cxx
@@ -22,13 +22,43 @@
 #define OBJECT2
 #define FUNC(x) FUNC2(x)
 #define FUNC2(x)
-#define FUNC_GEN3() anything
-#define FUNC_GEN4(x) anything
-  
+#define FUNC_GEN() ()
+#define FUNC_GEN2(x) ()
+#define FUNC_GEN3() (&)
+#define FUNC_GEN4(x) (y)
+#define FUNC_GEN5() (y,z)
+#define FUNC_GEN6() anything
+#define FUNC_GEN7(x) anything
+
 #if defined(BOOST_PP_VARIADICS_MSVC)
 
+#define FUNC_GEN8(x,y) (1,2,3)
+#define FUNC_GEN9(x,y,z) anything
+  
+/* These next five produce the wrong result in VC++ */
+
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN) == 1 END
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN2) == 1 END
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN3) == 1 END
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN4) == 1 END
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN5) == 1 END
+
+/* This next should produce a compiler error but does not, and produces the incorrect result */
+
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN8) == 1 END
+
+/* This next should produce a compiler error but does not */
+
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN9) == 0 END
+
 #else
 
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN) == 0 END
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN2) == 0 END
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN3) == 0 END
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN4) == 0 END
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN5) == 0 END
+
 #endif
 
 BEGIN BOOST_PP_IS_EMPTY(BOOST_PP_EMPTY()) == 1 END
@@ -36,7 +66,7 @@ BEGIN BOOST_PP_IS_EMPTY(DATA BOOST_PP_EMPTY()) == 1 END
 BEGIN BOOST_PP_IS_EMPTY(x BOOST_PP_EMPTY()) == 0 END
 BEGIN BOOST_PP_IS_EMPTY(OBJECT BOOST_PP_EMPTY()) == 1 END
 BEGIN BOOST_PP_IS_EMPTY(FUNC(z) BOOST_PP_EMPTY()) == 1 END
-BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN3) == 0 END
-BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN4) == 0 END
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN6) == 0 END
+BEGIN BOOST_PP_IS_EMPTY(FUNC_GEN7) == 0 END
   
 #endif