From d8bce5ec58a66a06dff82533c638a5ba382f7740 Mon Sep 17 00:00:00 2001
From: NumbFish <numbfish@yeah.net>
Date: Thu, 13 Feb 2020 05:48:59 +0800
Subject: [PATCH] fix bug: In Visual Stido, __VA_ARGS__ is treated as a
 separate parameter

---
 cloak.h | 67 ++++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 45 insertions(+), 22 deletions(-)

diff --git a/cloak.h b/cloak.h
index 0619587..28b0908 100644
--- a/cloak.h
+++ b/cloak.h
@@ -8,17 +8,24 @@
 #ifndef CLOAK_GUARD_H
 #define CLOAK_GUARD_H
 
+/* fix bug: In Visual Stido, __VA_ARGS__ is treated as a separate parameter */
+#define FIX_VS_BUG(x) x
+
+/* catenate */
+#define PRIMITIVE_CAT(a, ...) FIX_VS_BUG(a ## __VA_ARGS__)
 #define CAT(a, ...) PRIMITIVE_CAT(a, __VA_ARGS__)
-#define PRIMITIVE_CAT(a, ...) a ## __VA_ARGS__
 
+/* unary complement (bit inversion) */
 #define COMPL(b) PRIMITIVE_CAT(COMPL_, b)
 #define COMPL_0 1
 #define COMPL_1 0
 
+/* BITAND(x)(y) => x & y */
 #define BITAND(x) PRIMITIVE_CAT(BITAND_, x)
 #define BITAND_0(y) 0
 #define BITAND_1(y) y
 
+/* increase */
 #define INC(x) PRIMITIVE_CAT(INC_, x)
 #define INC_0 1
 #define INC_1 2
@@ -30,7 +37,9 @@
 #define INC_7 8
 #define INC_8 9
 #define INC_9 9
+/* ... */
 
+/* decrease */
 #define DEC(x) PRIMITIVE_CAT(DEC_, x)
 #define DEC_0 0
 #define DEC_1 0
@@ -42,37 +51,43 @@
 #define DEC_7 6
 #define DEC_8 7
 #define DEC_9 8
+/* ... */
 
+/* run the 2nd param */
 #define CHECK_N(x, n, ...) n
-#define CHECK(...) CHECK_N(__VA_ARGS__, 0,)
+#define CHECK(...) FIX_VS_BUG(CHECK_N(__VA_ARGS__, 0,))
 #define PROBE(x) x, 1,
 
-#define IS_PAREN(x) CHECK(IS_PAREN_PROBE x)
+/* PROBE(~) => ~, 1, */
 #define IS_PAREN_PROBE(...) PROBE(~)
+/* IS_PAREN(xxx) => 0 */
+/* IS_PAREN((xxx)) => 1 */
+#define IS_PAREN(x) CHECK(IS_PAREN_PROBE x)
 
 #define NOT(x) CHECK(PRIMITIVE_CAT(NOT_, x))
 #define NOT_0 PROBE(~)
 
-#define COMPL(b) PRIMITIVE_CAT(COMPL_, b)
-#define COMPL_0 1
-#define COMPL_1 0
-
 #define BOOL(x) COMPL(NOT(x))
 
 #define IIF(c) PRIMITIVE_CAT(IIF_, c)
+/* run the 2nd param */
 #define IIF_0(t, ...) __VA_ARGS__
+/* run the 1st param */
 #define IIF_1(t, ...) t
 
 #define IF(c) IIF(BOOL(c))
 
 #define EAT(...)
 #define EXPAND(...) __VA_ARGS__
+/* WHEN(0)(...) => EXPAND(...) => ... */
+/* WHEN(1)(...) => EAT(...) => *nothing* */
 #define WHEN(c) IF(c)(EXPAND, EAT)
 
 #define EMPTY()
 #define DEFER(id) id EMPTY()
 #define OBSTRUCT(id) id DEFER(EMPTY)()
 
+/* evaluate? */
 #define EVAL(...)  EVAL1(EVAL1(EVAL1(__VA_ARGS__)))
 #define EVAL1(...) EVAL2(EVAL2(EVAL2(__VA_ARGS__)))
 #define EVAL2(...) EVAL3(EVAL3(EVAL3(__VA_ARGS__)))
@@ -80,41 +95,49 @@
 #define EVAL4(...) EVAL5(EVAL5(EVAL5(__VA_ARGS__)))
 #define EVAL5(...) __VA_ARGS__
 
+/* EVAL(REPEAT(3, A, B)) => A(0, B) A(1, B) A(2, B) */
 #define REPEAT(count, macro, ...) \
-    WHEN(count) \
-    ( \
-        OBSTRUCT(REPEAT_INDIRECT) () \
-        ( \
+    WHEN(count) ( \
+        OBSTRUCT(REPEAT_INDIRECT) () ( \
             DEC(count), macro, __VA_ARGS__ \
         ) \
-        OBSTRUCT(macro) \
-        ( \
+        OBSTRUCT(macro) ( \
             DEC(count), __VA_ARGS__ \
         ) \
     )
 #define REPEAT_INDIRECT() REPEAT
 
+/*
+    EVAL(WHILE(A, B, C)) =>
+    while (A(C)) {
+        C = B(C).args[0];
+        // DARK MAGIC ~
+    }
+    return args;
+*/
 #define WHILE(pred, op, ...) \
-    IF(pred(__VA_ARGS__)) \
-    ( \
-        OBSTRUCT(WHILE_INDIRECT) () \
-        ( \
+    IF(pred(__VA_ARGS__)) ( \
+        OBSTRUCT(WHILE_INDIRECT) () ( \
             pred, op, op(__VA_ARGS__) \
         ), \
         __VA_ARGS__ \
     )
 #define WHILE_INDIRECT() WHILE
 
-#define PRIMITIVE_COMPARE(x, y) IS_PAREN \
-( \
-    COMPARE_ ## x ( COMPARE_ ## y) (())  \
+/*
+    #define COMPARE_foo(x) x
+    #define COMPARE_bar(x) x
+    PRIMITIVE_COMPARE(foo, bar) // Expands to 1
+    PRIMITIVE_COMPARE(foo, foo) // Expands to 0
+*/
+#define PRIMITIVE_COMPARE(x, y) IS_PAREN ( \
+    COMPARE_ ## x ( COMPARE_ ## y) (()) \
 )
 
 #define IS_COMPARABLE(x) IS_PAREN( CAT(COMPARE_, x) (()) )
 
 #define NOT_EQUAL(x, y) \
-IIF(BITAND(IS_COMPARABLE(x))(IS_COMPARABLE(y)) ) \
-( \
+IIF(BITAND(IS_COMPARABLE(x))(IS_COMPARABLE(y))) ( \
    PRIMITIVE_COMPARE, \
    1 EAT \
 )(x, y)