Mercurial > lasercutter
view src/clojure/contrib/zip_filter/xml.clj @ 10:ef7dbbd6452c
added clojure source goodness
author | Robert McIntyre <rlm@mit.edu> |
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date | Sat, 21 Aug 2010 06:25:44 -0400 |
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1 ; Copyright (c) Chris Houser, April 2008. All rights reserved.2 ; The use and distribution terms for this software are covered by the3 ; Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)4 ; which can be found in the file epl-v10.html at the root of this distribution.5 ; By using this software in any fashion, you are agreeing to be bound by6 ; the terms of this license.7 ; You must not remove this notice, or any other, from this software.9 ; Specialization of zip-filter for xml trees.11 (ns clojure.contrib.zip-filter.xml12 (:require [clojure.contrib.zip-filter :as zf]13 [clojure.zip :as zip]14 [clojure.xml :as xml]))16 (declare xml->)18 (defn attr19 "Returns the xml attribute named attrname, of the xml node at location loc."20 ([attrname] (fn [loc] (attr loc attrname)))21 ([loc attrname] (when (zip/branch? loc) (-> loc zip/node :attrs attrname))))23 (defn attr=24 "Returns a query predicate that matches a node when it has an25 attribute named attrname whose value is attrval."26 [attrname attrval] (fn [loc] (= attrval (attr loc attrname))))28 (defn tag=29 "Returns a query predicate that matches a node when its is a tag30 named tagname."31 [tagname]32 (fn [loc]33 (filter #(and (zip/branch? %) (= tagname ((zip/node %) :tag)))34 (if (zf/auto? loc)35 (zf/children-auto loc)36 (list (zf/auto true loc))))))38 (defn text39 "Returns the textual contents of the given location, similar to40 xpaths's value-of"41 [loc]42 (.replaceAll43 ^String (apply str (xml-> loc zf/descendants zip/node string?))44 (str "[\\s" (char 160) "]+") " "))46 (defn text=47 "Returns a query predicate that matches a node when its textual48 content equals s."49 [s] (fn [loc] (= (text loc) s)))51 (defn seq-test52 "Returns a query predicate that matches a node when its xml content53 matches the query expresions given."54 ^{:private true}55 [preds] (fn [loc] (and (seq (apply xml-> loc preds)) (list loc))))57 (defn xml->58 "The loc is passed to the first predicate. If the predicate returns59 a collection, each value of the collection is passed to the next60 predicate. If it returns a location, the location is passed to the61 next predicate. If it returns true, the input location is passed to62 the next predicate. If it returns false or nil, the next predicate63 is not called.65 This process is repeated, passing the processed results of each66 predicate to the next predicate. xml-> returns the final sequence.67 The entire chain is evaluated lazily.69 There are also special predicates: keywords are converted to tag=,70 strings to text=, and vectors to sub-queries that return true if71 they match.73 See the footer of zip-query.clj for examples."74 [loc & preds]75 (zf/mapcat-chain loc preds76 #(cond (keyword? %) (tag= %)77 (string? %) (text= %)78 (vector? %) (seq-test %))))80 (defn xml1->81 "Returns the first item from loc based on the query predicates82 given. See xml->"83 [loc & preds] (first (apply xml-> loc preds)))86 ; === examples ===88 (comment90 (defn parse-str [s]91 (zip/xml-zip (xml/parse (new org.xml.sax.InputSource92 (new java.io.StringReader s)))))94 (def atom1 (parse-str "<?xml version='1.0' encoding='UTF-8'?>95 <feed xmlns='http://www.w3.org/2005/Atom'>96 <id>tag:blogger.com,1999:blog-28403206</id>97 <updated>2008-02-14T08:00:58.567-08:00</updated>98 <title type='text'>n01senet</title>99 <link rel='alternate' type='text/html' href='http://n01senet.blogspot.com/'/>100 <entry>101 <id>1</id>102 <published>2008-02-13</published>103 <title type='text'>clojure is the best lisp yet</title>104 <author><name>Chouser</name></author>105 </entry>106 <entry>107 <id>2</id>108 <published>2008-02-07</published>109 <title type='text'>experimenting with vnc</title>110 <author><name>agriffis</name></author>111 </entry>112 </feed>113 "))115 ; simple single-function filter116 (assert (= (xml-> atom1 #((zip/node %) :tag))117 '(:feed)))119 ; two-stage filter using helpful query prediates120 (assert (= (xml-> atom1 (tag= :title) text)121 '("n01senet")))123 ; same filter as above, this time using keyword shortcut124 (assert (= (xml-> atom1 :title text)125 '("n01senet")))127 ; multi-stage filter128 (assert (= (xml-> atom1 :entry :author :name text)129 '("Chouser" "agriffis")))131 ; test xml1->132 (assert (= (xml1-> atom1 :entry :author :name text)133 "Chouser"))135 ; multi-stage filter with subquery specified using a vector136 (assert (= (xml-> atom1 :entry [:author :name (text= "agriffis")]137 :id text)138 '("2")))140 ; same filter as above, this time using a string shortcut141 (assert (= (xml-> atom1 :entry [:author :name "agriffis"] :id text)142 '("2")))144 ; attribute access145 (assert (= (xml-> atom1 :title (attr :type))146 '("text")))148 ; attribute filtering149 (assert (= (xml-> atom1 :link [(attr= :rel "alternate")] (attr :type))150 '("text/html")))152 ; ancestors153 (assert (= (xml-> atom1 zf/descendants :id "2" zf/ancestors zip/node #(:tag %))154 '(:id :entry :feed)))156 ; ancestors with non-auto tag= (:entry), followed by auto tag= (:id)157 (assert (= (xml-> atom1 zf/descendants :name "Chouser" zf/ancestors158 :entry :id text)159 '("1")))161 ; left-locs and detection of returning a single loc (zip/up)162 (assert (= (xml-> atom1 zf/descendants :name "Chouser" zip/up163 zf/left-locs :id text)164 '("1")))166 ; right-locs167 (assert (= (xml-> atom1 zf/descendants :id zf/right-locs :author text)168 '("Chouser" "agriffis")))170 )