Re: Elisp: Simple function to Add Two Numbers

[Barry Margolin <barmar@alum.mit.edu>]

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
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