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
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