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* bug#26635: 25.1; elisp docs bug
@ 2017-04-24  3:35 zhangjg
  2017-04-24  9:59 ` Andreas Schwab
  0 siblings, 1 reply; 4+ messages in thread
From: zhangjg @ 2017-04-24  3:35 UTC (permalink / raw)
  To: 26635

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The elisp docs in the session "12.1 What Is a Function?" distinction the funtion and the function-like object.
But in some pages, some function-like object is give as a function. 
For example:
In session "3.4 Comparison of Numbers", "=" is a set to a "function" but, in fact it a "special forms".

In the same resason, I think, "<", "<=", ">", ">=" also should be "special forms".

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^ permalink raw reply	[flat|nested] 4+ messages in thread

* bug#26635: 25.1; elisp docs bug
  2017-04-24  3:35 bug#26635: 25.1; elisp docs bug zhangjg
@ 2017-04-24  9:59 ` Andreas Schwab
  2017-04-24 10:31   ` bug#26635: 回复: " zhangjg
  0 siblings, 1 reply; 4+ messages in thread
From: Andreas Schwab @ 2017-04-24  9:59 UTC (permalink / raw)
  To: zhangjg; +Cc: 26635

On Apr 24 2017, "zhangjg" <jinguozhang@qq.com> wrote:

> In session "3.4 Comparison of Numbers", "=" is a set to a "function" but, in fact it a "special forms".

Why do you think `=' is a special form?

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."





^ permalink raw reply	[flat|nested] 4+ messages in thread

* bug#26635: 回复: bug#26635: 25.1; elisp docs bug
  2017-04-24  9:59 ` Andreas Schwab
@ 2017-04-24 10:31   ` zhangjg
  2017-04-24 10:50     ` Andreas Schwab
  0 siblings, 1 reply; 4+ messages in thread
From: zhangjg @ 2017-04-24 10:31 UTC (permalink / raw)
  To: Andreas Schwab; +Cc: 26635

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Like the fellow code:

  (= 1 1 t) ; error
  (= 1 2 t) ; nil

t is a symbol, (= 1 1 t) signal a error, that is what we expect. 
But in the second form there is no error, because  "=" get the
result before to eval the third argument "t". 
So "=" not to eval all arguments, that is  a "sepecial form" activation.




------------------ 原始邮件 ------------------
发件人: "Andreas Schwab";<schwab@linux-m68k.org>;
发送时间: 2017年4月24日(星期一) 下午5:59
收件人: "zhangjg"<jinguozhang@qq.com>; 
抄送: "26635"<26635@debbugs.gnu.org>; 
主题: Re: bug#26635: 25.1; elisp docs bug



On Apr 24 2017, "zhangjg" <jinguozhang@qq.com> wrote:

> In session "3.4 Comparison of Numbers", "=" is a set to a "function" but, in fact it a "special forms".

Why do you think `=' is a special form?

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

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^ permalink raw reply	[flat|nested] 4+ messages in thread

* bug#26635: 回复: bug#26635: 25.1; elisp docs bug
  2017-04-24 10:31   ` bug#26635: 回复: " zhangjg
@ 2017-04-24 10:50     ` Andreas Schwab
  0 siblings, 0 replies; 4+ messages in thread
From: Andreas Schwab @ 2017-04-24 10:50 UTC (permalink / raw)
  To: zhangjg; +Cc: 26635

On Apr 24 2017, "zhangjg" <jinguozhang@qq.com> wrote:

> Like the fellow code:
>
>   (= 1 1 t) ; error
>   (= 1 2 t) ; nil
>
> t is a symbol, (= 1 1 t) signal a error, that is what we expect. 
> But in the second form there is no error, because  "=" get the
> result before to eval the third argument "t". 

All arguments are evaluated, by the caller.  Try (= 1 2 (foo)), for
example.

> So "=" not to eval all arguments, that is  a "sepecial form" activation.

It may _ignore_ some of its arguments, but that's not what `special
form' is about.  Any function is free to ignore arguments.

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."





^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2017-04-24 10:50 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2017-04-24  3:35 bug#26635: 25.1; elisp docs bug zhangjg
2017-04-24  9:59 ` Andreas Schwab
2017-04-24 10:31   ` bug#26635: 回复: " zhangjg
2017-04-24 10:50     ` Andreas Schwab

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