Common Lisp有幾百個函式，不可能把所有的函式用法都記得很清楚，所以就希望在編寫程式時可以隨時的檢視函式的文件描述。

首先，我找到documentation函式，其用法是：

 (documentation 'symbol 'type)

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."
 

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

所以，我希望找到一種可以檢視任何函式的方法。

最後，我在slime的manual中找到了檢視函式文件的命令：

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.
 

越來越感覺，只要正確設定好，lisp的互動環境比python的互動環境更強大。