cppmagic: Iteration

[ccan] / ccan / cppmagic / cppmagic.h

diff --git a/ccan/cppmagic/cppmagic.h b/ccan/cppmagic/cppmagic.h
index 8acbba71a68d4e97c849831f7b5abd55bcc4f1fe..f1f6868e550dd2377d8829fec8a62d88bc842d1d 100644 (file)
--- a/ccan/cppmagic/cppmagic.h
+++ b/ccan/cppmagic/cppmagic.h
@@ -133,4 +133,59 @@
 #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 */