Rewrite FOR macro, to allow zero fixed arguments if desired

.gitignore

@@ -1 +1,3 @@
 *.pyc
+.zig-cache
+zig-out

book/pages/reference/enum.md

@@ -0,0 +1,4 @@
+# Enum utilities
+
+:::{doxygenfile} enum.h
+:::

book/pages/reference/index.md

@@ -4,4 +4,5 @@
 internal
 color
 log
+enum
 :::

build.zig

@@ -4,6 +4,6 @@ pub fn build(b: *std.Build) void {
     b.installDirectory(.{
         .source_dir = b.path("include/blackmagic"),
         .install_dir = .header,
-        .install_subdir = "blackmagic"
+        .install_subdir = "blackmagic",
     });
 }

build.zig.zon

@@ -1,5 +1,5 @@
 .{
-	.name = "Blackmagic",
-	.version = "0.2.0",
-	.paths = .{"include"}
+    .name = "blackmagic",
+    .version = "0.2.0",
+    .paths = .{ "build.zig", "build.zig.zon", "include", "README.md", "LICENSE" },
 }

include/blackmagic/blackmagic.h

@@ -6,12 +6,12 @@
  * @author Antoine GAGNIERE
  */
 
-#include "blackmagic/token.h"
-#include "blackmagic/log.h"
-#include "blackmagic/for.h"
 #include "blackmagic/color.h"
 #include "blackmagic/enum.h"
 #include "blackmagic/fold.h"
+#include "blackmagic/for.h"
+#include "blackmagic/log.h"
+#include "blackmagic/token.h"
 
 /**
  * @dir include

include/blackmagic/enum.h

@@ -9,6 +9,7 @@
 
 #include <stdbool.h> // bool
 
+///@cond
 #define PP_PAIR_APPLY(F, P) F P
 #define PP_PAIR_ASSIGN(K, V) K = V
 #define PP_PAIR_FIRST(K, V) K
@@ -17,6 +18,7 @@
 
 #define _ECNT(N) _MERGE(N, count)
 #define _EMAX(N) _MERGE(N, upper_bound)
+///@endcond
 
 /**
 @code{.c}

include/blackmagic/for.h

@@ -1,5 +1,8 @@
 #pragma once
 
+#include "blackmagic/arg_count.h" // ARG_COUNT
+#include "blackmagic/token.h" // CONCAT
+
 /**
  * @file
  * Generate code by calling a macro repeatedly
@@ -9,18 +12,46 @@
 #define EACH(...) ARG_COUNT(__VA_ARGS__) __VA_OPT__(,) __VA_ARGS__
 
 /**
- * Call @p MACRO on each item of the @p LIST, forwarding extra arguments if any
- * # Example
+ * Call @p MACRO on each item of the @p LIST, forwarding extra arguments if any.
+ * __Example__
  * @code{.c}
  * FOR(EACH(A, B, C), F, X, Y)
  * @endcode
  * will expand to:
  * @code{.c}
- * F(A, X, Y)
- * F(B, X, Y)
- * F(C, X, Y)
+ * F(X, Y, A)
+ * F(X, Y, B)
+ * F(X, Y, C)
  * @endcode
  * @param LIST shall be of the form `EACH(P0, P1, ..., Pn-1)`
  * @param MACRO shall be a function-like macro
+ * @since 0.2
  */
-#define FOR(LIST, MACRO, ...) _FOR(LIST, MACRO __VA_OPT__(,) __VA_ARGS__)
+#define FOR(LIST, MACRO, ...) FOR_(LIST, MACRO __VA_OPT__(,) __VA_ARGS__)
+
+///@cond
+#define FOR_(N, ...)  CONCAT(FOR_, N)(__VA_ARGS__)
+#define FOR_0(M, ...)
+#define FOR_1(A, M, ...)          M(__VA_ARGS__ __VA_OPT__(,) A)
+#define FOR_2(A, B, M, ...)       M(__VA_ARGS__ __VA_OPT__(,) A) M(__VA_ARGS__ __VA_OPT__(,) B)
+#define FOR_3(A, B, C, M, ...)    M(__VA_ARGS__ __VA_OPT__(,) A) M(__VA_ARGS__ __VA_OPT__(,) B) M(__VA_ARGS__ __VA_OPT__(,) C)
+#define FOR_4(A, B, C, D, M, ...) M(__VA_ARGS__ __VA_OPT__(,) A) M(__VA_ARGS__ __VA_OPT__(,) B) M(__VA_ARGS__ __VA_OPT__(,) C) M(__VA_ARGS__ __VA_OPT__(, ) D)
+#define FOR_5(A, B, C, D, E, M, ...) \
+	M(__VA_ARGS__ __VA_OPT__(,) A) \
+	FOR_4(B, C, D, E, M __VA_OPT__(,) __VA_ARGS__)
+#define FOR_6(A, B, C, D, E, F, M, ...) \
+	FOR_3(A, B, C, M __VA_OPT__(,) __VA_ARGS__)	\
+	FOR_3(D, E, F, M __VA_OPT__(,) __VA_ARGS__)
+#define FOR_7(A, B, C, D, E, F, G, M, ...) \
+	M(__VA_ARGS__ __VA_OPT__(,) A) \
+	FOR_6(B, C, D, E, F, G, M __VA_OPT__(,) __VA_ARGS__)
+#define FOR_8(A, B, C, D, E, F, G, H, M, ...) \
+	FOR_4(A, B, C, D, M __VA_OPT__(,) __VA_ARGS__) \
+	FOR_4(E, F, G, H, M __VA_OPT__(,) __VA_ARGS__)
+#define FOR_9(A, B, C, D, E, F, G, H, I, M, ...) \
+	M(__VA_ARGS__ __VA_OPT__(,) A) \
+	FOR_8(B, C, D, E, F, G, H, I, M __VA_OPT__(,) __VA_ARGS__)
+#define FOR_10(A, B, C, D, E, F, G, H, I, J, M, ...) \
+	FOR_5(A, B, C, D, E, M __VA_OPT__(,) __VA_ARGS__) \
+	FOR_5(F, G, H, I, J, M __VA_OPT__(,) __VA_ARGS__)
+///@endcond