easily create simple evil-mode text objects

evil-custom-objects.el

; courtesy of Gordon Gustafson on StackOverflow
; originally posted 2014-03-15
; http://stackoverflow.com/questions/18102004/emacs-evil-mode-how-to-create-a-new-text-object-to-select-words-with-any-non-sp

(defmacro define-and-bind-text-object (key start-regex end-regex)
  (let ((inner-name (make-symbol "inner-name"))
        (outer-name (make-symbol "outer-name")))
    `(progn
      (evil-define-text-object ,inner-name (count &optional beg end type)
        (evil-regexp-range count beg end type ,start-regex ,end-regex t))
      (evil-define-text-object ,outer-name (count &optional beg end type)
        (evil-regexp-range count beg end type ,start-regex ,end-regex nil))
      (define-key evil-inner-text-objects-map ,key (quote ,inner-name))
      (define-key evil-outer-text-objects-map ,key (quote ,outer-name)))))

;;; Useage:

; between dollars sign:
(define-and-bind-text-object "$" "\\$" "\\$")

; between pipe characters:
(define-and-bind-text-object "|" "|" "|")

; from the letter b up to the letter c, bound to k (invoke with "vik"):
(define-and-bind-text-object "k" "b" "c")