option macros

src/macros/concatenate.h

@@ -0,0 +1,8 @@
+#ifndef CONCATENATE_H
+#define CONCATENATE_H
+
+#define m_concatenate(p_a, p_b)   m_concatenate_(p_a, p_b)
+#define m_concatenate_(p_a, p_b)  m_concatenate__(p_a, p_b)
+#define m_concatenate__(p_a, p_b) p_a##p_b
+
+#endif

src/macros/option.h

@@ -0,0 +1,65 @@
+#ifndef OPTION_H
+#define OPTION_H
+
+#include "concatenate.h"
+#include "varargcount.h"
+
+#include <stdbool.h>
+
+/* usage example:
+ *
+ * struct result {
+ *     float f;
+ *     m_option_list(
+ *         int, v
+ *     )
+ * }
+ *
+ * struct result = {
+ *     m_set(f, 1.0), -- non options could be set with this
+ *     m_opt(v, 5),   -- options are supposed to be initialized like that
+ * }
+ *
+ */
+
+#define m_set(p_member, p_value) .p_member = (p_value)
+
+#define m_opt(p_member, p_value) .p_member##_opt = (p_value), .p_member##_opt_set = 1
+
+#define m_is_set(p_value, p_member) ((p_value).p_member##_opt_set)
+
+/* warn: beware of double evaluation! */
+#define m_or(p_value, p_member, p_default) ((p_value).p_member##_opt_set ? (p_value).p_member##_opt : (p_default))
+
+#define m_option_list_2(t0, m0) \
+        t0 m0##_opt;            \
+        bool m0##_opt_set : 1;  \
+
+#define m_option_list_4(t0, m0, t1, m1) \
+        t0 m0##_opt;                    \
+        t1 m1##_opt;                    \
+        bool m0##_opt_set : 1;          \
+        bool m1##_opt_set : 1;          \
+
+#define m_option_list_6(t0, m0, t1, m1, t2, m2) \
+        t0 m0##_opt;                            \
+        t1 m1##_opt;                            \
+        t2 m1##_opt;                            \
+        bool m0##_opt_set : 1;                  \
+        bool m1##_opt_set : 1;                  \
+        bool m2##_opt_set : 1;                  \
+
+#define m_option_list_8(t0, m0, t1, m1, t2, m2, t3, m3) \
+        t0 m0##_opt;                                    \
+        t1 m1##_opt;                                    \
+        t2 m2##_opt;                                    \
+        t3 m3##_opt;                                    \
+        bool m0##_opt_set : 1;                          \
+        bool m1##_opt_set : 1;                          \
+        bool m2##_opt_set : 1;                          \
+        bool m3##_opt_set : 1;                          \
+
+#define m_option_list_(p_n, ...) m_concatenate(m_option_list_, p_n)(__VA_ARGS__)
+#define m_option_list(...)       m_option_list_(m_narg(__VA_ARGS__), __VA_ARGS__)
+
+#endif

src/macros/varargcount.h

@@ -0,0 +1,9 @@
+#ifndef VARARGCOUNT_H
+#define VARARGCOUNT_H
+
+#define m_narg(...) m_narg_(__VA_ARGS__, m_rseq_n_())
+#define m_narg_(...) m_arg_n_(__VA_ARGS__) 
+#define m_arg_n_(_1, _2, _3, _4, _5, _6, _7, _8, N, ...) N 
+#define m_rseq_n_() 8, 7, 6, 5, 4, 3, 2, 1, 0
+
+#endif