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Re: elisp: can a function/defun return two strings..? prompt for two str


From: Tim X
Subject: Re: elisp: can a function/defun return two strings..? prompt for two strings??
Date: Mon, 28 Feb 2011 08:10:49 +1100
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/24.0.50 (gnu/linux)

ken <address@hidden> writes:

> In one line of a file/buffer (which might exist or might not) will be
> two strings, both of which must be fetched and returned to the calling
> function.  I was going to write two separate functions, one for each
> string, but since both strings are in the same line, it seemed highly
> inefficient to search for the same line of text twice... made more sense
> to search for it once, and get both strings in the same function.
>
> Here's pseudo-code:
>
> ;; search buffer for line of interest.
> ;; if the line exists
>   ;; does it specify str1?
>   ;; if it does, grab that str1, hold it for eventual return
>   ;; if it doesn't, prompt user for it, and hold it for eventual return.
>   ;; does the same line specify str2?
>   ;; if it does, grab that str2, hold it for eventual return
>   ;; if it doesn't, prompt user for it, and hold it for eventual return.
> ;; if the line doesn't exist,
>   ;; prompt user for str1 and str2
>      ;; create/insert new line in buffer, inserting str1 & str2 into it.
> ;; return str1 and str2 to calling function
>
> Most of the coding for the above will busy itself with finding the line
> of interest-- or determining that it doesn't exist.  So why should I do
> that twice, once for each string?  Sure, I could save to a variable the
> location of the line of interest to avoid having to search for it again,
> but then I'm back to working with two variables, the location and just
> one string.  So that's a non-solution.
>
> So how to "return" two variables to a calling function, possibly have to
> prompt for one or both of them?  (I can think of a half dozen ways to do
> this in C, but this is elisp.)
>
>

Just return the strings as a list of two strings i.e. 

     (list str1 str2)

Tim

-- 
tcross (at) rapttech dot com dot au


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