Elisp: Simple function to Add Two Numbers

Elisp: Simple function to Add Two Numbers

[Edward Dodge]

Please,

Why do I get "wrong number of arguments" every time I try to run this simple,
straight-forward code?

(defun ekd-average (jabba wabba)
  "Adds two numbers and returns the sum."
  (interactive "nFirstvar: \nn Secondvar: \nr")
     ( + jabba wabba))


-- 
Edward Dodge
          
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 _`\(,_   
(_)/ (_)  ---  --- 

Re: Elisp: Simple function to Add Two Numbers

[Hadron Quark]

Edward Dodge <user@foo.bar> writes:

> Please,
>
> Why do I get "wrong number of arguments" every time I try to run this simple,
> straight-forward code?
>
> (defun ekd-average (jabba wabba)
>   "Adds two numbers and returns the sum."
>   (interactive "nFirstvar: \nn Secondvar: \nr")
>      ( + jabba wabba))
>

As a fellow beginner I would say its because you havent properly
specified your second argument string in the interactive
statement. Check whitespace.

Re: Elisp: Simple function to Add Two Numbers

[Pascal Bourguignon]

Hadron Quark <hadronquark@gmail.com> writes:

> Edward Dodge <user@foo.bar> writes:
>
>> Please,
>>
>> Why do I get "wrong number of arguments" every time I try to run this simple,
>> straight-forward code?
>>
>> (defun ekd-average (jabba wabba)
>>   "Adds two numbers and returns the sum."
>>   (interactive "nFirstvar: \nn Secondvar: \nr")
>>      ( + jabba wabba))
>>
>
> As a fellow beginner I would say its because you havent properly
> specified your second argument string in the interactive
> statement. Check whitespace.

The whitespaces don't matter, as long as they're not just after a
newline.  The problem is that there are two newlines with three
characters specifying a total of four interactive arguments: n, n and r.
(r gives two arguments, start and end of region).


-- 
__Pascal Bourguignon__                     http://www.informatimago.com/

READ THIS BEFORE OPENING PACKAGE: According to certain suggested
versions of the Grand Unified Theory, the primary particles
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four hundred million years.

Re: Elisp: Simple function to Add Two Numbers

[Magnus Henoch]

Edward Dodge <user@foo.bar> writes:

> Why do I get "wrong number of arguments" every time I try to run this simple,
> straight-forward code?
>
> (defun ekd-average (jabba wabba)
>   "Adds two numbers and returns the sum."
>   (interactive "nFirstvar: \nn Secondvar: \nr")
>      ( + jabba wabba))

The trailing "r" in the interactive string means to give the region as
argument to the function, in the form of two integers telling the
beginning and the end.  Remove "\nr" in the end, and the function will
work.

Magnus

Re: Elisp: Simple function to Add Two Numbers

[David Kastrup]

Edward Dodge <user@foo.bar> writes:

> Please,
>
> Why do I get "wrong number of arguments" every time I try to run this simple,
> straight-forward code?
>
> (defun ekd-average (jabba wabba)
>   "Adds two numbers and returns the sum."
>   (interactive "nFirstvar: \nn Secondvar: \nr")
>      ( + jabba wabba))

Because the arguments would need to be
(jabba wabba region-start region-end)

You are aware what the final "r" in your interactive spec means?

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum

Re: Elisp: Simple function to Add Two Numbers

[Edward Dodge]

Pascal Bourguignon <pjb@informatimago.com> writes:


> The whitespaces don't matter, as long as they're not just after a
> newline.  The problem is that there are two newlines with three
> characters specifying a total of four interactive arguments: n, n and r.
> (r gives two arguments, start and end of region).

Yes,  this is correct.  And I have managed to keep the function from causing
an error by rewriting it:

(defun ekd-average (jabba wabba)
  "Adds two numbers and returns the difference between"
  (interactive "nFirstvar: \nnSecondvar: ")
     (eval ( + jabba wabba)))

Now the only problem is this:  it returns no answer when I run it.  I thought
lisp functions always returned a value.  I even made it explicit by using the
"eval" statement,  but still I get no answer in either the minibuffer or
*Messages*.

-- 
Edward Dodge
          
   __o    
 _`\(,_   
(_)/ (_)  ---  --- 

Re: Elisp: Simple function to Add Two Numbers

[Barry Margolin]

In article <ihq64gdtz97.fsf@chlr7032.ch.intel.com>,
 Edward Dodge <user@foo.bar> wrote:

> Pascal Bourguignon <pjb@informatimago.com> writes:
> 
> 
> > The whitespaces don't matter, as long as they're not just after a
> > newline.  The problem is that there are two newlines with three
> > characters specifying a total of four interactive arguments: n, n and r.
> > (r gives two arguments, start and end of region).
> 
> Yes,  this is correct.  And I have managed to keep the function from causing
> an error by rewriting it:
> 
> (defun ekd-average (jabba wabba)
>   "Adds two numbers and returns the difference between"
>   (interactive "nFirstvar: \nnSecondvar: ")
>      (eval ( + jabba wabba)))

You don't need eval.

> 
> Now the only problem is this:  it returns no answer when I run it.  I thought
> lisp functions always returned a value.  I even made it explicit by using the
> "eval" statement,  but still I get no answer in either the minibuffer or
> *Messages*.

Yes, the function returns a value.  But your command never displays the 
value anywhere, and M-x doesn't automatically display the return value 
of functions.  Use (print (+ jabba wabba)) and it will be displayed in 
the echo area.

-- 
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***
*** PLEASE don't copy me on replies, I'll read them in the group ***

Re: Elisp: Simple function to Add Two Numbers

[Edward Dodge]

Barry Margolin <barmar@alum.mit.edu> writes:

> Yes, the function returns a value.  But your command never displays the 
> value anywhere, and M-x doesn't automatically display the return value 
> of functions.  Use (print (+ jabba wabba)) and it will be displayed in 
> the echo area.

That was it!  Thank-you very much!

-- 
Edward Dodge
          
   __o    
 _`\(,_   
(_)/ (_)  ---  ---