摘要：A familiar source of questions on the R mailing lists is the newly converted R user who is trying to write SAS or Stata code in R. Bill Venables then points out to them that R is not a macro language, and gently explains that there is a much easier solution to their problems. In this article I will explain what a macro is, why it’s good that R isn’t a macro language, and how to make it into one. There are two reasons for this. It has been famously observed1 that a Real Programmer can write Fortran code in any language, and it is similarly an interesting exercise to see how R can implement macros. Secondly, there are a few tasks for which macros are genuinely useful, which is why languages like LISP, for example, provide them.
