Podle 1.12 How can I annotate Ruby code with its result

str = "Billy" + " Bob"          # => "Billy Bob"
str[0,1] + str[2,1] + str[-2,2] # => "Blob"

Integrace do Emacsu

(defun ruby-xmp-region (reg-start reg-end)
  "Pipe the region through Ruby's xmp utility and replace the \
region with the result."
  (interactive "r")
  (shell-command-on-region reg-start reg-end
      "ruby -r xmp -n -e 'xmp($_, \"%l\t\t# %r\n\")'"
      t))