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Re: (goto-char ...) error


From: Deniz Dogan
Subject: Re: (goto-char ...) error
Date: Tue, 22 Feb 2011 18:31:03 +0100

2011/2/22 ken <address@hidden>:
> Performing one search, I save the result with
>
> (setq ptname (re-search-forward ...))
>
> Then I want to back up one character and perform another search, so I do
>
> (goto-char (- ptname 1))
>
> But this pukes an error.  What's unkosher here?
>

It's much easier if you tell us what the error is.

I tried to reproduce the problem using this code:

;; search for "a"
(let ((ptname (re-search-forward "a" nil t)))
  (when ptname
    (goto-char (- ptname 1))))

It all depends on how you use re-search-forward. As you can see in my
example, I pass t as the third argument meaning "don't error if you
can't find it, just return nil". I then make sure that ptname is
non-nil before I try to act on it using `-', otherwise we would be
doing (- nil 1) which makes no sense.

-- 
Deniz Dogan



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