A key binding not working

  (:mode in-math?) 
  ("1 /" (begin 
              (math-insert '(frac "1" ""))) 

the (kbd-left) does not work. It has no effect of moving the cursor.

Why is this? What is the alternative way?

1 Like

Firstly, I find that if I use Debug -> Execute -> Evaluate Scheme Expression..., the single (kbd-left) works as expected.

Secondly, I will look into how (kbd-left) is implemented. Using Help->Search->Source Code... to search (kbd-left), I found:

(tm-define (kbd-left)
  (kbd-horizontal (focus-tree) #f))

(tm-define (kbd-horizontal t forwards?)
  (:require (tree-is-buffer? t))
  (with move (lambda () (if forwards? (go-right) (go-left)))
    (go-to-next-such-that move generic-context?)))

(tm-define (traverse-horizontal t forwards?)
  (if forwards? (go-to-next-word) (go-to-previous-word)))

I do know why kbd-left and go-left does not work as expected. but go-to-previous-word works fine.

Finally, the you may use the following code snippet:

(kbd-map (:mode in-math?)
         ("1 /" (begin (math-insert `(frac "1" ""))

As a matter of fact, I have found traverse-previous. It does not work somehow. I forgot to try others in the family. I turns out that traverse-left works.


(kbd-map (:mode in-math?)
      ("p / p" (begin (math-insert '(frac "<partial>" "<partial>")))

will move the cursor to the beginning of denominator. I tried traverse-right and traverse-next after (go-to-previous-word) to put the cursor at the end of the denominator. It does not work. Somehow, (go-to-next-word) works.

I have achiedved what I want. It is put in the code

("p / p" (begin (math-insert '(frac "<partial>" "<partial>"))

But it seems still strange that (go-to-next-word) and (go-to-previous-word) are not inverse to each other in this instance.

Thank you.