X-Git-Url: https://git.ozlabs.org/?a=blobdiff_plain;f=ccan%2Fcppmagic%2Fcppmagic.h;h=f1f6868e550dd2377d8829fec8a62d88bc842d1d;hb=f359fde1b7c3ca60faebd4df710bf30a68784e27;hp=b5c35782f78ca5e58ab16fa45bddb0649c87333c;hpb=395a2f841356e5bba4935a24093d30d67c1f3ef5;p=ccan

diff --git a/ccan/cppmagic/cppmagic.h b/ccan/cppmagic/cppmagic.h
index b5c35782..f1f6868e 100644
--- a/ccan/cppmagic/cppmagic.h
+++ b/ccan/cppmagic/cppmagic.h
@@ -98,4 +98,94 @@
 #define CPPMAGIC_IFELSE(cond_)		\
 	_CPPMAGIC_IFELSE(CPPMAGIC_NONZERO(cond_))
 
+/**
+ * CPPMAGIC_EVAL - force multiple expansion passes
+ *
+ * Forces macros in the arguments to be expanded repeatedly (up to
+ * 1024 times) even when CPP would usually stop expanding.
+ */
+#define CPPMAGIC_EVAL1(...)		__VA_ARGS__
+#define CPPMAGIC_EVAL2(...)		\
+	CPPMAGIC_EVAL1(CPPMAGIC_EVAL1(__VA_ARGS__))
+#define CPPMAGIC_EVAL4(...)		\
+	CPPMAGIC_EVAL2(CPPMAGIC_EVAL2(__VA_ARGS__))
+#define CPPMAGIC_EVAL8(...)		\
+	CPPMAGIC_EVAL4(CPPMAGIC_EVAL4(__VA_ARGS__))
+#define CPPMAGIC_EVAL16(...)		\
+	CPPMAGIC_EVAL8(CPPMAGIC_EVAL8(__VA_ARGS__))
+#define CPPMAGIC_EVAL32(...)		\
+	CPPMAGIC_EVAL16(CPPMAGIC_EVAL16(__VA_ARGS__))
+#define CPPMAGIC_EVAL64(...)		\
+	CPPMAGIC_EVAL32(CPPMAGIC_EVAL32(__VA_ARGS__))
+#define CPPMAGIC_EVAL128(...)		\
+	CPPMAGIC_EVAL64(CPPMAGIC_EVAL64(__VA_ARGS__))
+#define CPPMAGIC_EVAL256(...)		\
+	CPPMAGIC_EVAL128(CPPMAGIC_EVAL128(__VA_ARGS__))
+#define CPPMAGIC_EVAL512(...)		\
+	CPPMAGIC_EVAL256(CPPMAGIC_EVAL256(__VA_ARGS__))
+#define CPPMAGIC_EVAL1024(...)		\
+	CPPMAGIC_EVAL512(CPPMAGIC_EVAL512(__VA_ARGS__))
+#define CPPMAGIC_EVAL(...)		CPPMAGIC_EVAL1024(__VA_ARGS__)
+
+/**
+ * CPPMAGIC_DEFER1, CPPMAGIC_DEFER2 - defer expansion
+ */
+#define CPPMAGIC_DEFER1(a_)	a_ CPPMAGIC_NOTHING()
+#define CPPMAGIC_DEFER2(a_)	a_ CPPMAGIC_NOTHING CPPMAGIC_NOTHING()()
+
+/**
+ * CPPMAGIC_MAP - iterate another macro across arguments
+ * @m: name of a one argument macro
+ *
+ * CPPMAGIC_MAP(@m, @a1, @a2, ... @an)
+ *	expands to the expansion of @m(@a1) , @m(@a2) , ... , @m(@an)
+ */
+#define _CPPMAGIC_MAP_()		_CPPMAGIC_MAP
+#define _CPPMAGIC_MAP(m_, a_, ...)					\
+	m_(a_)								\
+	CPPMAGIC_IFELSE(CPPMAGIC_NONEMPTY(__VA_ARGS__))			\
+		(, CPPMAGIC_DEFER2(_CPPMAGIC_MAP_)()(m_, __VA_ARGS__))	\
+		()
+#define CPPMAGIC_MAP(m_, ...)						\
+	CPPMAGIC_IFELSE(CPPMAGIC_NONEMPTY(__VA_ARGS__))			\
+		(CPPMAGIC_EVAL(_CPPMAGIC_MAP(m_, __VA_ARGS__)))		\
+		()
+
+/**
+ * CPPMAGIC_2MAP - iterate another macro across pairs of arguments
+ * @m: name of a two argument macro
+ *
+ * CPPMAGIC_2MAP(@m, @a1, @b1, @a2, @b2, ..., @an, @bn)
+ *	expands to the expansion of
+ *		 @m(@a1, @b1) , @m(@a2, @b2) , ... , @m(@an, @bn)
+ */
+#define _CPPMAGIC_2MAP_()		_CPPMAGIC_2MAP
+#define _CPPMAGIC_2MAP(m_, a_, b_, ...)				\
+	m_(a_, b_)							\
+	CPPMAGIC_IFELSE(CPPMAGIC_NONEMPTY(__VA_ARGS__))			\
+		(, CPPMAGIC_DEFER2(_CPPMAGIC_2MAP_)()(m_, __VA_ARGS__)) \
+		()
+#define CPPMAGIC_2MAP(m_, ...)					\
+	CPPMAGIC_IFELSE(CPPMAGIC_NONEMPTY(__VA_ARGS__))			\
+		(CPPMAGIC_EVAL(_CPPMAGIC_2MAP(m_, __VA_ARGS__)))	\
+		()
+
+/**
+ * CPPMAGIC_JOIN - separate arguments with given delimiter
+ * @d: delimiter
+ *
+ * CPPMAGIC_JOIN(@d, @a1, @a2, ..., @an)
+ *	expands to the expansion of @a1 @d @a2 @d ... @d @an
+ */
+#define _CPPMAGIC_JOIN_()		_CPPMAGIC_JOIN
+#define _CPPMAGIC_JOIN(d_, a_, ...)					\
+	a_								\
+	CPPMAGIC_IFELSE(CPPMAGIC_NONEMPTY(__VA_ARGS__))			\
+		(d_ CPPMAGIC_DEFER2(_CPPMAGIC_JOIN_)()(d_, __VA_ARGS__)) \
+		()
+#define CPPMAGIC_JOIN(d_, ...)					\
+	CPPMAGIC_IFELSE(CPPMAGIC_NONEMPTY(__VA_ARGS__))			\
+		(CPPMAGIC_EVAL(_CPPMAGIC_JOIN(d_, __VA_ARGS__)))	\
+		()
+
 #endif /* CCAN_CPPMAGIC_H */