mikaelj

  ## if
  val = func()
  if val:            # standard form
      code(val)      # of if

  ## aif
  aif(func, code)    # not obvious that it does the same thing
                     # and limits you to using a function defined
                     # elsewhere, or Python's crippled one-line lambda.

  ;; regular when
  (let (val (func))
    (when val        ; standard form
      (func val)))   ; of when

  ;; awhen
  (awhen (func)     ; standard form of
    (func it)       ; when, with added bound value
    ; possibly other
    ; code goes here
    )