internal/range.h rework

Eliminate macros for better readability.

internal/range.h

@@ -9,10 +9,29 @@
  *             modify this file, provided that  the conditions mentioned in the
  *             file COPYING are met.  Consult the file for details.
  */
+#include "internal/struct.h"    /* for RSTRUCT */
 
 /* range.c */
-#define RANGE_BEG(r) (RSTRUCT(r)->as.ary[0])
-#define RANGE_END(r) (RSTRUCT(r)->as.ary[1])
-#define RANGE_EXCL(r) (RSTRUCT(r)->as.ary[2])
+static inline VALUE RANGE_BEG(VALUE r);
+static inline VALUE RANGE_END(VALUE r);
+static inline VALUE RANGE_EXCL(VALUE r);
+
+static inline VALUE
+RANGE_BEG(VALUE r)
+{
+    return RSTRUCT(r)->as.ary[0];
+}
+
+static inline VALUE
+RANGE_END(VALUE r)
+{
+    return RSTRUCT(r)->as.ary[1];
+}
+
+static inline VALUE
+RANGE_EXCL(VALUE r)
+{
+    return RSTRUCT(r)->as.ary[2];
+}
 
 #endif /* INTERNAL_RANGE_H */