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Re: Function-Problem
From: |
tomas |
Subject: |
Re: Function-Problem |
Date: |
Wed, 17 Aug 2016 15:27:56 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
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On Wed, Aug 17, 2016 at 12:49:11PM +0200, Klaus Jantzen wrote:
> Hello,
>
> the attached function should return true if a line contains all blanks
> or is empty.
>
> Currently the function returns a quick 'nil' and then the message
>
> "No catch for tag: --cl-block-nil--, nil"
>
> What is my problem?
>
> =====
> (defun blank-line-p ()
> "Returns t if line contains all blanks or is empty"
> (let ((lep (line-end-position))
> (cpp (point)) ; the current position
> (res 0)
> )
> (beginning-of-line)
> (if (re-search-forward "^[ ]+$\|^$" lep t)
> (progn (goto-char cpp) ; line is blank/empty
> (message "t")
> t)
> (progn (goto-char cpp) ; line is not blank/empty
> (message "nil")
> (return nil))
^^^^^^
I guess you just want to say `nil' there instead of `(return nil)'
(return is a wrapper around a CL exception which you haven't caught
"upstairs", thus the funny message).
> )
> ) ; end of let
> ) ; end of 'blank-line-p'
> ====
> Thanks for any hint.
Note that you can have it much easier. Cf `looking-at', e.g.
(beginning-of-line)
(looking-at "^[ ]*$")
might be roughly equivalent to your code snippet above.
Perhaps you want to use "save-excursion" if you don't want your
function to leave point at a different position it started:
(defun blank-line-p ()
(save-excursion
(beginning-of-line)
(looking-at "^[ ]*$")))
You might also want to refine the regexp to include other
whitespace characters besides of " " (e.g. the POSIX class
[:space:] or some such).
Regards
- -- t
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