last-input-event and X/non-X

last-input-event and X/non-X

[Tim X]

I have some code which uses last-input-event to test what was last
entered by the user. However, I've noticed that this value can vary
depending on whether you are running under X or within a console. I'm
wondering what the standard emacs lisp idiom is for handling this. 

As an example, I have some code in a conditional which is like

((= last-input-event 127)
 (do-somehting))

Under the console, this block will execute if the user hits backspace
to indicate a character has been deleted. However, if I execute this
code under X, I will get a wrong-type-argument number-or-marker-p
backspace error. This is because under X, rather than a number,
last-input-event will hold the symbol 'backspace. 

Now, I could fix this by doing something like
((or (eq last-input-event 127) 
     (eq last-input-event 'backspace)) 
 (do-something)) 

but that seems a bit clunky to me. Also, I'm not sure how well this
will work with other character sets or encodings or on other
platforms, like Windows. 

Any advice appreciated.

thanks,

Tim

-- 
tcross (at) rapttech dot com dot au

Re: last-input-event and X/non-X

[Miles Bader]

Tim X <timx@nospam.dev.null> writes:
> ((or (eq last-input-event 127) 
>      (eq last-input-event 'backspace)) 
>  (do-something)) 
>
> but that seems a bit clunky to me. Also, I'm not sure how well this
> will work with other character sets or encodings or on other
> platforms, like Windows. 

You might try looking up the event in `function-key-map', which is how
platform-specific things like <backspace> normally get translated.

e.g. 

    (when (equal (lookup-key function-key-map (vector last-input-event))
                 [127])
       (do something))
       
-Miles    
-- 
"Suppose He doesn't give a shit?  Suppose there is a God but He
just doesn't give a shit?"  [George Carlin]

Re: last-input-event and X/non-X

[Tim X]

Miles Bader <miles@gnu.org> writes:

> Tim X <timx@nospam.dev.null> writes:
>> ((or (eq last-input-event 127) 
>>      (eq last-input-event 'backspace)) 
>>  (do-something)) 
>>
>> but that seems a bit clunky to me. Also, I'm not sure how well this
>> will work with other character sets or encodings or on other
>> platforms, like Windows. 
>
> You might try looking up the event in `function-key-map', which is how
> platform-specific things like <backspace> normally get translated.
>
> e.g. 
>
>     (when (equal (lookup-key function-key-map (vector last-input-event))
>                  [127])
>        (do something))
>        

thanks Miles - that is a good idea. I was actually just delving into
the key maps as I figured there had to be something like that. You
have saved me a bit of time by narrowing the search space a bit.
Thanks.

Tim


-- 
tcross (at) rapttech dot com dot au