From: lee <lee@yun.yagibdah.de>
To: help-gnu-emacs@gnu.org
Subject: Re: replacing a function with another one
Date: Sat, 15 Mar 2014 20:51:23 +0100 [thread overview]
Message-ID: <878usbw890.fsf@yun.yagibdah.de> (raw)
In-Reply-To: <87siqmy39r.fsf@web.de> (Michael Heerdegen's message of "Thu, 13 Mar 2014 08:19:12 +0100")
Michael Heerdegen <michael_heerdegen@web.de> writes:
> lee <lee@yun.yagibdah.de> writes:
>
>> and it doesn´t work because end-marker is undefined despite I just
>> defined it :( So I have
>>
>>
>> (let ((end-marker (concat "^" comment-start lsl-hi-lock-patterns-end-marker)))
>> (let ((marker-pos (re-search-forward end-marker (point-max) t)))
>> (do-something)))
>>
>
> The functionality you want, and that you reached with the nested `let',
> is exactly what `let*' does. When I was learning LISP, I was also
> confused about `let'. Standard `let' first evaluates all
> expressions, then binds the variables, so in works "parallel" - see
Ah! Finally I understand what the difference is! What is the point of
having two variations of `let'?
> [...]
>> (let ((patterns nil))
>> (while (< (point) marker-pos)
>> (setq patterns (append (read (current-buffer)) patterns)))
>> (setq patterns patterns)))))))
>>
>>
>> I need this function to return `patterns'. Without the last line, it
>> seems to return nil because the setq is enclosed in the while.
>
> `let' returns the value returned by the last body expression (in
> particular, that isn't necessarily the value of the variable `patterns'
> in your example!). And `while' always returns nil (strictly speaking,
> the return value isn't documented, so don't rely on it at all). So this
> is what you want:
>
> (let ((patterns nil))
> (while (< (point) marker-pos)
> (setq patterns (append (read (current-buffer)) patterns)))
> patterns)
Thank you --- I only found that out yesterday. It makes sense when you
think that a symbol stands for itself --- which is probably not correct,
but I just think of it as that the variable stands for itself and can be
returned like that.
--
Knowledge is volatile and fluid. Software is power.
next prev parent reply other threads:[~2014-03-15 19:51 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-08 19:43 replacing a function with another one lee
2014-03-08 19:54 ` Eli Zaretskii
2014-03-09 1:17 ` lee
2014-03-08 22:30 ` Michael Heerdegen
2014-03-09 17:58 ` lee
2014-03-09 19:10 ` Michael Heerdegen
2014-03-09 20:57 ` lee
2014-03-09 22:02 ` Michael Heerdegen
2014-03-10 0:53 ` lee
2014-03-10 2:18 ` Michael Heerdegen
2014-03-10 15:29 ` lee
2014-03-11 0:03 ` Michael Heerdegen
2014-03-11 13:34 ` lee
2014-03-11 23:40 ` Michael Heerdegen
2014-03-12 6:11 ` Michael Heerdegen
2014-03-12 7:07 ` Michael Heerdegen
2014-03-12 14:48 ` lee
2014-03-13 7:19 ` Michael Heerdegen
2014-03-15 19:51 ` lee [this message]
2014-03-17 12:00 ` Michael Heerdegen
2014-03-12 14:04 ` lee
2014-03-12 18:26 ` Stefan Monnier
2014-03-12 4:10 ` Michael Heerdegen
2014-03-10 12:44 ` Stefan Monnier
2014-03-10 23:35 ` lee
2014-03-11 0:41 ` Michael Heerdegen
2014-03-11 1:45 ` Michael Heerdegen
2014-03-11 19:05 ` lee
2014-03-11 22:58 ` Michael Heerdegen
2014-03-12 15:11 ` lee
2014-03-12 18:15 ` Stefan Monnier
2014-03-12 21:43 ` lee
2014-03-13 7:22 ` Michael Heerdegen
2014-03-15 20:02 ` lee
2014-03-11 4:11 ` lee
2014-03-11 5:01 ` Michael Heerdegen
2014-03-11 14:25 ` lee
2014-03-11 23:51 ` Michael Heerdegen
2014-03-12 15:22 ` lee
2014-03-13 7:33 ` Michael Heerdegen
2014-03-13 12:29 ` Stefan Monnier
2014-03-15 20:05 ` lee
2014-03-16 17:20 ` Stefan
2014-03-11 6:51 ` Michael Heerdegen
2014-03-11 15:41 ` lee
2014-03-11 23:21 ` Michael Heerdegen
2014-03-12 17:33 ` lee
2014-03-12 19:34 ` Florian Beck
2014-03-12 19:51 ` Florian Beck
2014-03-13 7:54 ` Michael Heerdegen
2014-03-15 20:14 ` lee
2014-03-12 12:45 ` Stefan Monnier
2014-03-12 17:42 ` lee
2014-03-13 2:43 ` Jambunathan K
2014-03-15 20:17 ` How to propose an emacs patch (Re: replacing a function with another one) lee
2014-03-16 3:21 ` Jambunathan K
2014-03-17 4:35 ` lee
2014-03-10 13:45 ` replacing a function with another one lee
2014-03-10 23:31 ` Michael Heerdegen
2014-03-12 13:16 ` Jambunathan K
2014-03-12 13:18 ` Jambunathan K
2014-03-15 20:22 ` lee
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