From dd1a7c13f2ce730a9da83c4467ebd34778a88c9d Mon Sep 17 00:00:00 2001
From: Patrick Pelissier <patrick.pelissier@gmail.com>
Date: Sat, 18 Mar 2017 20:38:59 +0100
Subject: [PATCH] Add MACRO M_VA

---
 m-core.h           | 17 ++++++++++++++---
 tests/test-mcore.c |  8 ++++++++
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/m-core.h b/m-core.h
index 5690130a..0e673d89 100644
--- a/m-core.h
+++ b/m-core.h
@@ -794,6 +794,15 @@ m_core_hash(const void *ptr, size_t s)
 #define M_IF_METHOD_ALL(method, ...)                            \
   M_IF(M_REDUCE2(M_TEST_METHOD_P, M_AND, method, __VA_ARGS__))
 
+/* By putting this after a method, we transform the argument list
+   so that the first argument becomes a pointer to the destination. */
+#define M_IPTR(...) ( & __VA_ARGS__ )
+
+
+/************************************************************/
+/******************** Syntax Enhancing **********************/
+/************************************************************/
+
 /* Define M_EACH macro allowing to iterate over a container
    First argument will be a created pointer to the underlying type.
    Example: for M_EACH(item, list, LIST_OPLIST) { action; } */
@@ -824,6 +833,7 @@ m_core_hash(const void *ptr, size_t s)
           !M_GET_IT_END_P oplist (iterator) && (item = M_GET_IT_CREF oplist (iterator), true) ; \
           M_GET_IT_NEXT oplist (iterator))
 
+
 /* Define M_LET macro allowing to define, auto init & auto clear an object
    within the next bracket.
    Example:
@@ -847,9 +857,10 @@ m_core_hash(const void *ptr, size_t s)
       cont && (M_GET_INIT oplist (name), true);                         \
       (M_GET_CLEAR oplist (name), cont = false))
 
-/* By putting this after a method, we transform the argument list
-   so that the first argument becomes a pointer to the destination. */
-#define M_IPTR(...) ( & __VA_ARGS__ )
+/* Transform the va list by adding their number as the first argument of
+   the list.
+   Example:   M_VA(a,b,c,d,e) ==> 5,a,b,c,d,e */
+#define M_VA(...) M_NARGS(__VA_ARGS__), __VA_ARGS__
 
 
 /************************************************************/
diff --git a/tests/test-mcore.c b/tests/test-mcore.c
index 5d9b0ea4..d718bed8 100644
--- a/tests/test-mcore.c
+++ b/tests/test-mcore.c
@@ -145,6 +145,13 @@ static void test_let(void)
   }
 }
 
+static void test_va(void)
+{
+  assert (M_RET_ARG1 (M_VA(a),zz) == 1);
+  assert (M_RET_ARG2 (M_VA(17),zz) == 17);
+  assert (M_RET_ARG1 (M_VA(a,b,c),zz) == 3);
+  assert (M_RET_ARG2 (M_VA(17,42,59),zz) == 17);
+}
 
 int main(void)
 {
@@ -155,5 +162,6 @@ int main(void)
   test_invert();
   test_min();
   test_let();
+  test_va();
   exit(0);
 }