In most lisp-like languages, there is a distinction between functions (standard evaluation) and macros (non-standard evaluation). A given callable is either one

In most lisp-like languages, there is a distinction between functions (standard evaluation) and macros (non-standard evaluation). A given callable is either one or the other. In R, every function is both, since it can access both the evaluated and unevaluated forms of each of its arguments.