Lisp 如果找到匹配项，则返回一行文本

如果找到匹配项，我很难确定如何返回一行文本

(set 'wireshark "http://anonsvn.wireshark.org/wireshark/trunk/manuf")

(set 'arptable (map (fn (x) (parse x " ")) (exec "arp -a")))

(define (cleanIPaddress x)
  (slice x 1 -1))

(define (cleanMACaddress x) 
  (upper-case (join (slice (parse x ":") 0 3) ":")))

(define (addIPandMACaddress x) 
  (list (cleanIPaddress (nth 1 x)) (cleanMACaddress (nth 3 x))))

(set 'arplist (map addIPandMACaddress arptable))

(set 'routerMAC (last (assoc (exec "ipconfig getoption en1 router") arplist)))

(find-all routerMAC (get-url wireshark))

返回

（“20:AA:4B”）

所以我知道代码“有效”

但我想检索全文

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“20:AA:4B Cisco Li#Cisco Linksys，LLC”

这可以通过使用

字符串拆分

过程来执行，该过程允许我们使用

删除if

（通用Lisp版本的

过滤器

）通过新行分割的字符串进行搜索，删除不包含我们正在搜索的字符串的任何行。这将产生包含字符串的每一行的列表。我们将在这里定义的函数已经通过各种常见的Lisp库提供，但是出于教育目的，我们将自己定义它们。您需要的代码是这样工作的：

; First we need a function to split a string by character

(defun string-split (split-string string)
  (loop with l = (length split-string)
        for n = 0 then (+ pos l)
        for pos = (search split-string string :start2 n)
        if pos collect (subseq string n pos)
        else collect (subseq string n)
        while pos))

; Now we will make a function based on string-split to split by newlines

(defun newline-split (string)
  (string-split "
" string))

; Finally, we go through our text searching for lines that match our string.
; Make sure to replace 'needle' with the string you wish to search for.

(remove-if #'(lambda (x) 
               (equal 'nil (search (string-upcase "needle") 
                                   (string-upcase x))))
           (newline-split haystack))

您应该能够对发布的代码应用此策略，只需进行一些小的修改。该代码在Mac OS X 10.7.5上的SBCL 1.0.55.0-abb03f9（ANSI Common Lisp的实现）上进行了测试。

最后我使用了：

(find-all (string routerMAC ".*") (get-url wireshark))

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Wireshark项目于2014年1月从Subversion转向Git。“manuf”URL现在是