XPath implementation in Clojure

最新推荐文章于 2017-06-21 17:46:46 发布

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#clojure #command #header #import

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本文介绍了如何在Clojure中实现XPath支持的功能，并通过具体的代码示例进行了详细说明。

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The functions to support using XPath in Clojure.

Source Code

1 ;The code was implemented by caichao@amazon.com
2 ;You could use the code anyway, but should keep the comments
3 ;Created 2012.10
4 (ns clojure.ccsoft.xml
5   (:require [clojure.xml :as xml]))
6
7 (import '(java.io StringReader)
8         '(java.io ByteArrayInputStream))
9
10 (defn xml-structure [xml-txt]
11    [ (xml/parse (-> xml-txt
12               (.getBytes)
13               (ByteArrayInputStream.)
14      )
15     )]
16 )
17
18 (defn node [tag xmlStruct]
19
20   (first (filter #(= (:tag %) tag) (:content xmlStruct)))
21 )
22
23 (defn node [path xml-txt]
24    (loop [path path
25           xml-content (xml-structure xml-txt)
26           ]
27       (let [current-tag (first path) current-elem (first xml-content)]
28         (if (= (:tag current-elem ) current-tag)
29
30           (if (= (count path) 1)
31             current-elem
32             (recur  (rest path) (:content current-elem ))
33           )
34           (if (> (count  xml-content) 1)
35            (recur path  (rest xml-content))
36           )
37         )
38      )
39     )
40  )

How to Use

(def cmd-example "<command>
                   <header>
                     <type>script</type>
                     <transaction_id>12345</transaction_id>
                   </header>
                   <body>
                      println 3+4;
                   </body>
                  </command>")

(node [:command :header :transaction_id] cmd-example)