(defvar apl-keyboard '(
;; number row
"`◊   1¨   2¯   3<   4≤   5=   6≥   7>   8≠   9∨   0∧   -×   =÷  \⍝  |⍀" 

;; number row SHIFTed
"~⍨   !¡   @€   #£   $⍧   %    ^    &    *⍂   (⍱   )⍲   _≡   +⌹"

;; qwert row
"q?   w⍵   e∈   t∼   y↑   r⍴   u↓   i⍳   o○   p⋆"

;;  qwert row shifted
"Q¿   W⌽   E⋸   T⍉   Y¥   I⍸   O⍥   P⍟   [←   ]→"

;;  asdf row
"a⍺   s⌈   d⌊   f_   g∇   h∆   j∘   k'   l⎕   ;⊢   '⊣"

;;   asdf row shifted
"A⊖   S    D    F⍫   G⍒   H⍋   J⍤   K⌻   L⍞"

;; zxcv row
"z⊂   x⊃   c∩   v∪   b⊥   n⊤   m∣   ,⌷   .⍎   /⍕"

;; zxcv row shifted
"Z    X    C⍝   V    B⍎   N⍕   M⌶   <⍪   >⍙   ?⌿"

)
"APL keyboard is a list of keyboard rows
For structure see \\[kb-block-defrules]
"
)

(defun kb-block-defrules (kb)
  "kb is a list of keyboard rows
Each row is a space delimited string
The elements of the rows apart from spaces are a pair of characters
the first is a keyboard and the second is a translation (which could be absent)
See apl-keyboard above for example.
This function converts that list of strings 
into a lisp list of (key .translation) pairs
"
  (let ((kbl nil))
    (dolist (row kb (reverse kbl))
      (let ((key-trans-list (split-string row "[ \t]+" t))
	    (key) (trans))
	(dolist (key-trans key-trans-list)
	  (when (= (length key-trans) 2)
	    (setq key    (aref key-trans 0) 
		  trans  (aref key-trans 1)
		  kbl    (cons (cons key trans) kbl)
	     )))))))
    
(defvar apl-input-mode nil)

;; obviously this will not be global when the rest of apl mode
;; are in shape. Just a hack for now
(global-set-key (kbd "<Scroll_Lock>") 'toggle-apl-input-mode)

(defvar mode-name-aplized "απλ")
(defvar mode-name-ascii "APL")
(defvar apl-translation-table (make-translation-table 
			       (kb-block-defrules apl-keyboard)))

(defun toggle-apl-input-mode ()
  (interactive)
  (setq apl-input-mode (not apl-input-mode))
  (if apl-input-mode
      (setq keyboard-translate-table apl-translation-table
	    mode-name                mode-name-aplized)
    (setq keyboard-translate-table nil
	  mode-name                mode-name-ascii))
   (force-mode-line-update))