Possible to access previous arg in `interactice' call?

Possible to access previous arg in `interactice' call?

[Thorsten Jolitz]

Hi List, 

in this example, is there a way to access num1 while reading num2?

#+begin_src emacs-lisp
  (defun foo (num1 num2)
   (interactive
      (list
         (read-number "Num1: ")
         (+ (read-number "Num2: ") num1)))
   (message "num1: %s\nnum2: %s" num1 num2))
#+end_src

#+results:
: foo

#+begin_src emacs-lisp
 (call-interactively 'foo)
#+end_src

-> list: Symbol's value as variable is void: num1

-- 
cheers,
Thorsten

RE: Possible to access previous arg in `interactice' call?

[Drew Adams]

>    (interactive (list (read-number "Num1: ")
>                       (+ (read-number "Num2: ") num1)))
> 
> -> list: Symbol's value as variable is void: num1

Bind the value returned by the first `read-number' to a local
variable, and use that.

(interactive
  (let ((n1  (read-number "Num1: ")))
    (list n1 (+ (read-number "Num2: ") n1))))

Re: Possible to access previous arg in `interactice' call?

[Thorsten Jolitz]

Drew Adams <drew.adams@oracle.com> writes:

>>    (interactive (list (read-number "Num1: ")
>>                       (+ (read-number "Num2: ") num1)))
>> 
>> -> list: Symbol's value as variable is void: num1
>
> Bind the value returned by the first `read-number' to a local
> variable, and use that.
>
> (interactive
>   (let ((n1  (read-number "Num1: ")))
>     (list n1 (+ (read-number "Num2: ") n1))))

That works, thanks!

-- 
cheers,
Thorsten

Re: Possible to access previous arg in `interactice' call?

[Pascal J. Bourguignon]

Thorsten Jolitz <tjolitz@gmail.com> writes:

> Drew Adams <drew.adams@oracle.com> writes:
>
>>>    (interactive (list (read-number "Num1: ")
>>>                       (+ (read-number "Num2: ") num1)))
>>> 
>>> -> list: Symbol's value as variable is void: num1
>>
>> Bind the value returned by the first `read-number' to a local
>> variable, and use that.
>>
>> (interactive
>>   (let ((n1  (read-number "Num1: ")))
>>     (list n1 (+ (read-number "Num2: ") n1))))
>
> That works, thanks!

Indeed.  Remember that the point of the interactive _declaration_, is to
be able to get the argument _before_ the function is called.  Therefore
the parameters are not bound yet!

Declaration means that it's not _executed_ in the body of the command
It declares some behavior that is used before the command is called.

-- 
__Pascal Bourguignon__                 http://www.informatimago.com/
“The factory of the future will have only two employees, a man and a
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