Encountering void-variable sh-mode-map for define-key

Question

I am using the function tika-keymap-showhrk which takes a list of modes, then constructs the associated -map variable value for use with define-key.

But I get the error

Debugger entered--Lisp error: (void-variable sh-mode-map)
  symbol-value(sh-mode-map)

Here is the implementation code

(defun tika-keymap-showhrk (mdlist)
  "Bind key sequence in keymap to the outline-show-all command."
  (dolist (mjmode mdlist)
    (let ( ($map (symbol-value (intern (format "%s-map" mjmode)))) )
      (define-key $map (kbd "H-o a") #'outline-show-all))) )

(defvar tika-mjmode
  '(emacs-lisp-mode sh-mode f90-mode fortran-mode latex-mode
     plain-tex-mode) )

(defun tika-keymap-outlhrk ()
  "My Elisp stuff."
  (tika-keymap-showhrk tika-mjmode))

Answer 1

That variable is defined and its default value set in sh-script.el. If you want to take advantage of the bindings it defines, in addition to adding bindings to those, then you need to get that default definition by loading sh-script.el[c].

If for some reason you don't want to require sh-script.el when you invoke tika-keymap-showhrk, you can instead add a defvar that defines all of the bindings you want, including the default bindings. But then, if the default bindings change in some future Emacs release your defvar would need to be updated if you want to take advantage of those changes.

(defun tika-keymap-showhrk (mdlist)
  "Bind key sequence in keymap to the outline-show-all command."
  (require 'sh-script)  ; <============
  (dolist (mjmode  mdlist)
    (let (($map  (symbol-value (intern (format "%s-map" mjmode)))))
      (define-key $map (kbd "H-o a") #'outline-show-all))) )