如何查看common lisp函数的文档？

Common Lisp有几百个函数，不可能把所有的函数用法都记得很清楚，所以就希望在编写程序时可以随时的查看函数的文档描述。

首先，我找到documentation函数，其用法是：

 (documentation 'symbol 'type)

例如，我想查看make-hash-table函数，其用法和结果如下：

CL-USER> (documentation 'make-hash-table 'function)
"Create and return a new hash table. The keywords are as follows:

     :TEST -- Indicates what kind of test to use.

     :SIZE -- A hint as to how many elements will be put in this hash

       table.

     :REHASH-SIZE -- Indicates how to expand the table when it fills up.

       If an integer, add space for that many elements. If a floating

       point number (which must be greater than 1.0), multiply the size

       by that amount.

     :REHASH-THRESHOLD -- Indicates how dense the table can become before

       forcing a rehash. Can be any positive number <=1, with density

       approaching zero as the threshold approaches 0. Density 1 means an

       average of one entry per bucket."

这个返回结果信息很好。但是，对于一些函数如random，其返回的内容就很少：

CL-USER> (documentation 'random 'function)
NIL

所以，我希望找到一种可以查看任何函数的方法。

最后，我在slime的manual中找到了查看函数文档的命令：

C-c C-d h
M-x slime-hyperspec-lookup
Lookup the symbol at point in the Common Lisp Hyperspec. This uses the familiar hyperspec.el to show the appropriate section in a web browser. The Hyperspec is found either on the Web or in common-lisp-hyperspec-root, and the browser is selected by browse-url-browser-function.
Note: this is one case where C-c C-d h is not the same as C-c C-d C-h.

这个命令，默认情况下，会进行在线的查询，需要网络连接正常。为了在不方便上网的时候也可以查看函数文档，我们只需要把Hyperspec文档下载到本地，然后在文件hypersepc.el中修改变量common-lisp-hyperspec-root的值为你本地的路径（即存放Hyperspec文档的路径）。

越来越感觉，只要正确设置好，lisp的交互环境比python的交互环境更强大。