;;; -*- Mode:LISP; Package:LISP-INTERNALS; Readtable:CL; Base:10; Lowercase:T -*- ;;; ;;; ;;; COMMON-LISP-MACROS ;;; ;;;---------------------------------------------------------------------------- ;;; Conditionals ;;;---------------------------------------------------------------------------- (defmacro when (test &body forms) "WHEN evaluates the TEST form. If TEST evaluates to NIL, WHEN returns NIL. Otherwise, WHEN evaluates the list of FORMS and returns the value of the last one." `(IF ,test (PROGN ,@forms) NIL))