hxt-8.3.0: doc/hdoc/src/Text-XML-HXT-Arrow-XPath.html
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<pre><a name="line-1"></a><span class='comment'>-- ------------------------------------------------------------</span>
<a name="line-2"></a>
<a name="line-3"></a><span class='comment'>{- |
<a name="line-4"></a> Module : Text.XML.HXT.Arrow.XPath
<a name="line-5"></a> Copyright : Copyright (C) 2006 Uwe Schmidt
<a name="line-6"></a> License : MIT
<a name="line-7"></a>
<a name="line-8"></a> Maintainer : Uwe Schmidt (uwe@fh-wedel.de)
<a name="line-9"></a> Stability : experimental
<a name="line-10"></a> Portability: portable
<a name="line-11"></a>
<a name="line-12"></a> Arrows for working with XPath and XmlNodeSets.
<a name="line-13"></a>
<a name="line-14"></a> Most of the XPath arrows come in two versions,
<a name="line-15"></a> one without dealing with namespaces, element and attribute names
<a name="line-16"></a> in XPath expressions are taken as they ar ignoring any prefix:localname structure.
<a name="line-17"></a>
<a name="line-18"></a> The second variant uses a namespace environment for associating the right
<a name="line-19"></a> namespace for the appropriate prefix. an entry for the empty prefix
<a name="line-20"></a> defines the default namespace for the expression.
<a name="line-21"></a>
<a name="line-22"></a> The second variant should be used, when in the application namespaces
<a name="line-23"></a> are significant, that means when namespace propagation is done for
<a name="line-24"></a> the documents to be processed.
<a name="line-25"></a>
<a name="line-26"></a> NodeSets are sets of \"pointer\" into an XML tree to reference
<a name="line-27"></a> subnodes. These nodesets can be computed by XPath expressions or
<a name="line-28"></a> normal arrows. The nodesets can then be used later for selecting
<a name="line-29"></a> or modifying subtrees of this tree in an efficient way.
<a name="line-30"></a>
<a name="line-31"></a>-}</span>
<a name="line-32"></a>
<a name="line-33"></a><span class='comment'>-- ------------------------------------------------------------</span>
<a name="line-34"></a>
<a name="line-35"></a><span class='keyword'>module</span> <span class='conid'>Text</span><span class='varop'>.</span><span class='conid'>XML</span><span class='varop'>.</span><span class='conid'>HXT</span><span class='varop'>.</span><span class='conid'>Arrow</span><span class='varop'>.</span><span class='conid'>XPath</span>
<a name="line-36"></a> <span class='layout'>(</span> <span class='varid'>getXPathTreesInDoc</span>
<a name="line-37"></a> <span class='layout'>,</span> <span class='varid'>getXPathTreesInDocWithNsEnv</span>
<a name="line-38"></a> <span class='layout'>,</span> <span class='varid'>getXPathTrees</span>
<a name="line-39"></a> <span class='layout'>,</span> <span class='varid'>getXPathTreesWithNsEnv</span>
<a name="line-40"></a> <span class='layout'>,</span> <span class='varid'>getElemNodeSet</span>
<a name="line-41"></a> <span class='layout'>,</span> <span class='varid'>getElemAndAttrNodeSet</span>
<a name="line-42"></a> <span class='layout'>,</span> <span class='varid'>getXPathNodeSet</span>
<a name="line-43"></a> <span class='layout'>,</span> <span class='varid'>getFromNodeSet</span>
<a name="line-44"></a> <span class='layout'>,</span> <span class='varid'>processXPathTrees</span>
<a name="line-45"></a> <span class='layout'>,</span> <span class='varid'>processXPathTreesWithNsEnv</span>
<a name="line-46"></a> <span class='layout'>,</span> <span class='varid'>processFromNodeSet</span>
<a name="line-47"></a> <span class='layout'>)</span>
<a name="line-48"></a><span class='keyword'>where</span>
<a name="line-49"></a>
<a name="line-50"></a><span class='keyword'>import</span> <span class='keyword'>qualified</span> <span class='conid'>Text</span><span class='varop'>.</span><span class='conid'>XML</span><span class='varop'>.</span><span class='conid'>HXT</span><span class='varop'>.</span><span class='conid'>XPath</span> <span class='keyword'>as</span> <span class='conid'>PT</span>
<a name="line-51"></a> <span class='layout'>(</span> <span class='varid'>getXPathSubTreesWithNsEnv</span>
<a name="line-52"></a> <span class='layout'>,</span> <span class='varid'>getXPathNodeSetWithNsEnv</span>
<a name="line-53"></a> <span class='layout'>)</span>
<a name="line-54"></a>
<a name="line-55"></a><span class='keyword'>import</span> <span class='conid'>Control</span><span class='varop'>.</span><span class='conid'>Arrow</span><span class='varop'>.</span><span class='conid'>ListArrows</span>
<a name="line-56"></a>
<a name="line-57"></a><span class='keyword'>import</span> <span class='conid'>Text</span><span class='varop'>.</span><span class='conid'>XML</span><span class='varop'>.</span><span class='conid'>HXT</span><span class='varop'>.</span><span class='conid'>DOM</span><span class='varop'>.</span><span class='conid'>Interface</span>
<a name="line-58"></a><span class='keyword'>import</span> <span class='conid'>Text</span><span class='varop'>.</span><span class='conid'>XML</span><span class='varop'>.</span><span class='conid'>HXT</span><span class='varop'>.</span><span class='conid'>Arrow</span><span class='varop'>.</span><span class='conid'>XmlArrow</span>
<a name="line-59"></a>
<a name="line-60"></a><span class='keyword'>import</span> <span class='conid'>Text</span><span class='varop'>.</span><span class='conid'>XML</span><span class='varop'>.</span><span class='conid'>HXT</span><span class='varop'>.</span><span class='conid'>Arrow</span><span class='varop'>.</span><span class='conid'>Edit</span>
<a name="line-61"></a> <span class='layout'>(</span> <span class='varid'>canonicalizeForXPath</span>
<a name="line-62"></a> <span class='layout'>)</span>
<a name="line-63"></a>
<a name="line-64"></a><span class='comment'>-- ------------------------------------------------------------</span>
<a name="line-65"></a>
<a name="line-66"></a><span class='comment'>-- |</span>
<a name="line-67"></a><span class='comment'>-- Select parts of a whole XML document with root node by a XPath expression.</span>
<a name="line-68"></a><span class='comment'>--</span>
<a name="line-69"></a><span class='comment'>-- The main filter for selecting parts of a document via XPath.</span>
<a name="line-70"></a><span class='comment'>--</span>
<a name="line-71"></a><span class='comment'>-- The string argument must be a XPath expression with an absolute location path,</span>
<a name="line-72"></a><span class='comment'>-- the argument tree must be a complete document tree.</span>
<a name="line-73"></a><span class='comment'>--</span>
<a name="line-74"></a><span class='comment'>-- Before evaluating the xpath query, the document is canonicalized</span>
<a name="line-75"></a><span class='comment'>-- with 'Text.XML.HXT.Arrow.Edit.canonicalizeForXPath'</span>
<a name="line-76"></a><span class='comment'>--</span>
<a name="line-77"></a><span class='comment'>-- Result is a possibly empty list of XmlTrees forming the set of selected XPath values.</span>
<a name="line-78"></a><span class='comment'>-- XPath values other than XmlTrees (numbers, attributes, tagnames, ...)</span>
<a name="line-79"></a><span class='comment'>-- are convertet to text nodes.</span>
<a name="line-80"></a>
<a name="line-81"></a><a name="getXPathTreesInDoc"></a><span class='definition'>getXPathTreesInDoc</span> <span class='keyglyph'>::</span> <span class='conid'>ArrowXml</span> <span class='varid'>a</span> <span class='keyglyph'>=></span> <span class='conid'>String</span> <span class='keyglyph'>-></span> <span class='varid'>a</span> <span class='conid'>XmlTree</span> <span class='conid'>XmlTree</span>
<a name="line-82"></a><span class='definition'>getXPathTreesInDoc</span> <span class='keyglyph'>=</span> <span class='varid'>getXPathTreesInDocWithNsEnv</span> <span class='conid'>[]</span>
<a name="line-83"></a>
<a name="line-84"></a><span class='comment'>-- | Same as 'getXPathTreesInDoc' but with namespace environment for the XPath names</span>
<a name="line-85"></a>
<a name="line-86"></a><a name="getXPathTreesInDocWithNsEnv"></a><span class='definition'>getXPathTreesInDocWithNsEnv</span> <span class='keyglyph'>::</span> <span class='conid'>ArrowXml</span> <span class='varid'>a</span> <span class='keyglyph'>=></span> <span class='conid'>Attributes</span> <span class='keyglyph'>-></span> <span class='conid'>String</span> <span class='keyglyph'>-></span> <span class='varid'>a</span> <span class='conid'>XmlTree</span> <span class='conid'>XmlTree</span>
<a name="line-87"></a><span class='definition'>getXPathTreesInDocWithNsEnv</span> <span class='varid'>env</span> <span class='varid'>query</span> <span class='keyglyph'>=</span> <span class='varid'>canonicalizeForXPath</span>
<a name="line-88"></a> <span class='varop'>>>></span>
<a name="line-89"></a> <span class='varid'>arrL</span> <span class='layout'>(</span><span class='conid'>PT</span><span class='varop'>.</span><span class='varid'>getXPathSubTreesWithNsEnv</span> <span class='varid'>env</span> <span class='varid'>query</span><span class='layout'>)</span>
<a name="line-90"></a>
<a name="line-91"></a><span class='comment'>-- |</span>
<a name="line-92"></a><span class='comment'>-- Select parts of an arbitrary XML tree by a XPath expression.</span>
<a name="line-93"></a><span class='comment'>--</span>
<a name="line-94"></a><span class='comment'>-- The main filter for selecting parts of an arbitrary XML tree via XPath.</span>
<a name="line-95"></a><span class='comment'>-- The string argument must be a XPath expression with an absolute location path,</span>
<a name="line-96"></a><span class='comment'>-- There are no restrictions on the argument tree.</span>
<a name="line-97"></a><span class='comment'>--</span>
<a name="line-98"></a><span class='comment'>-- No canonicalization is performed before evaluating the query</span>
<a name="line-99"></a><span class='comment'>--</span>
<a name="line-100"></a><span class='comment'>-- Result is a possibly empty list of XmlTrees forming the set of selected XPath values.</span>
<a name="line-101"></a><span class='comment'>-- XPath values other than XmlTrees (numbers, attributes, tagnames, ...)</span>
<a name="line-102"></a><span class='comment'>-- are convertet to text nodes.</span>
<a name="line-103"></a>
<a name="line-104"></a><a name="getXPathTrees"></a><span class='definition'>getXPathTrees</span> <span class='keyglyph'>::</span> <span class='conid'>ArrowXml</span> <span class='varid'>a</span> <span class='keyglyph'>=></span> <span class='conid'>String</span> <span class='keyglyph'>-></span> <span class='varid'>a</span> <span class='conid'>XmlTree</span> <span class='conid'>XmlTree</span>
<a name="line-105"></a><span class='definition'>getXPathTrees</span> <span class='keyglyph'>=</span> <span class='varid'>getXPathTreesWithNsEnv</span> <span class='conid'>[]</span>
<a name="line-106"></a>
<a name="line-107"></a><span class='comment'>-- | Same as 'getXPathTrees' but with namespace environment for the XPath names</span>
<a name="line-108"></a>
<a name="line-109"></a><a name="getXPathTreesWithNsEnv"></a><span class='definition'>getXPathTreesWithNsEnv</span> <span class='keyglyph'>::</span> <span class='conid'>ArrowXml</span> <span class='varid'>a</span> <span class='keyglyph'>=></span> <span class='conid'>Attributes</span> <span class='keyglyph'>-></span> <span class='conid'>String</span> <span class='keyglyph'>-></span> <span class='varid'>a</span> <span class='conid'>XmlTree</span> <span class='conid'>XmlTree</span>
<a name="line-110"></a><span class='definition'>getXPathTreesWithNsEnv</span> <span class='varid'>env</span> <span class='varid'>query</span> <span class='keyglyph'>=</span> <span class='varid'>arrL</span> <span class='layout'>(</span><span class='conid'>PT</span><span class='varop'>.</span><span class='varid'>getXPathSubTreesWithNsEnv</span> <span class='varid'>env</span> <span class='varid'>query</span><span class='layout'>)</span>
<a name="line-111"></a>
<a name="line-112"></a><span class='comment'>-- | Select a set of nodes via an XPath expression from an arbitray XML tree</span>
<a name="line-113"></a><span class='comment'>--</span>
<a name="line-114"></a><span class='comment'>-- The result is a set of \"pointers\" to nodes. This set can be used to</span>
<a name="line-115"></a><span class='comment'>-- access or modify the values of the subnodes in subsequent calls to 'getFromNodeSet' or 'processFromNodeSet'.</span>
<a name="line-116"></a><span class='comment'>--</span>
<a name="line-117"></a><span class='comment'>-- This function enables for parsing an XPath expressions and traversing the tree for node selection once</span>
<a name="line-118"></a><span class='comment'>-- and reuse this result possibly many times for later selection and modification operations.</span>
<a name="line-119"></a>
<a name="line-120"></a><a name="getXPathNodeSet"></a><span class='definition'>getXPathNodeSet</span> <span class='keyglyph'>::</span> <span class='conid'>ArrowXml</span> <span class='varid'>a</span> <span class='keyglyph'>=></span> <span class='conid'>String</span> <span class='keyglyph'>-></span> <span class='varid'>a</span> <span class='conid'>XmlTree</span> <span class='conid'>XmlNodeSet</span>
<a name="line-121"></a><span class='definition'>getXPathNodeSet</span> <span class='keyglyph'>=</span> <span class='varid'>getXPathNodeSetWithNsEnv</span> <span class='conid'>[]</span>
<a name="line-122"></a>
<a name="line-123"></a><span class='comment'>-- | Same as 'getXPathNodeSet' but with namespace environment for the XPath names</span>
<a name="line-124"></a>
<a name="line-125"></a><a name="getXPathNodeSetWithNsEnv"></a><span class='definition'>getXPathNodeSetWithNsEnv</span> <span class='keyglyph'>::</span> <span class='conid'>ArrowXml</span> <span class='varid'>a</span> <span class='keyglyph'>=></span> <span class='conid'>Attributes</span> <span class='keyglyph'>-></span> <span class='conid'>String</span> <span class='keyglyph'>-></span> <span class='varid'>a</span> <span class='conid'>XmlTree</span> <span class='conid'>XmlNodeSet</span>
<a name="line-126"></a><span class='definition'>getXPathNodeSetWithNsEnv</span> <span class='varid'>nsEnv</span> <span class='varid'>query</span> <span class='keyglyph'>=</span> <span class='varid'>arr</span> <span class='layout'>(</span><span class='conid'>PT</span><span class='varop'>.</span><span class='varid'>getXPathNodeSetWithNsEnv</span> <span class='varid'>nsEnv</span> <span class='varid'>query</span><span class='layout'>)</span>
<a name="line-127"></a>
<a name="line-128"></a><span class='comment'>-- ------------------------------------------------------------</span>
<a name="line-129"></a>
<a name="line-130"></a><a name="getNodeSet"></a><span class='definition'>getNodeSet</span> <span class='keyglyph'>::</span> <span class='conid'>ArrowXml</span> <span class='varid'>a</span> <span class='keyglyph'>=></span> <span class='varid'>a</span> <span class='conid'>XmlTree</span> <span class='conid'>QName</span> <span class='keyglyph'>-></span> <span class='varid'>a</span> <span class='conid'>XmlTree</span> <span class='conid'>XmlTree</span> <span class='keyglyph'>-></span> <span class='varid'>a</span> <span class='conid'>XmlTree</span> <span class='conid'>XmlNodeSet</span>
<a name="line-131"></a><span class='definition'>getNodeSet</span> <span class='varid'>af</span> <span class='varid'>f</span>
<a name="line-132"></a> <span class='keyglyph'>=</span> <span class='layout'>(</span> <span class='layout'>(</span> <span class='varid'>listA</span> <span class='layout'>(</span> <span class='varid'>getChildren</span>
<a name="line-133"></a> <span class='varop'>>>></span>
<a name="line-134"></a> <span class='varid'>getNodeSet</span> <span class='varid'>af</span> <span class='varid'>f</span>
<a name="line-135"></a> <span class='layout'>)</span>
<a name="line-136"></a> <span class='varop'>>>></span>
<a name="line-137"></a> <span class='varid'>arr</span> <span class='varid'>filterNodeSet</span>
<a name="line-138"></a> <span class='layout'>)</span>
<a name="line-139"></a> <span class='varop'>&&&</span>
<a name="line-140"></a> <span class='varid'>listA</span> <span class='varid'>af</span>
<a name="line-141"></a> <span class='varop'>&&&</span>
<a name="line-142"></a> <span class='varid'>listA</span> <span class='varid'>f</span>
<a name="line-143"></a> <span class='layout'>)</span>
<a name="line-144"></a> <span class='varop'>>>^</span> <span class='layout'>(</span><span class='keyglyph'>\</span> <span class='keyglyph'>~</span><span class='layout'>(</span><span class='varid'>cl</span><span class='layout'>,</span> <span class='layout'>(</span><span class='varid'>al</span><span class='layout'>,</span> <span class='varid'>n</span><span class='layout'>)</span><span class='layout'>)</span> <span class='keyglyph'>-></span> <span class='conid'>XNS</span> <span class='layout'>(</span><span class='varid'>not</span> <span class='varop'>.</span> <span class='varid'>null</span> <span class='varop'>$</span> <span class='varid'>n</span><span class='layout'>)</span> <span class='varid'>al</span> <span class='varid'>cl</span><span class='layout'>)</span>
<a name="line-145"></a> <span class='keyword'>where</span>
<a name="line-146"></a> <span class='varid'>filterNodeSet</span> <span class='keyglyph'>::</span> <span class='keyglyph'>[</span><span class='conid'>XmlNodeSet</span><span class='keyglyph'>]</span> <span class='keyglyph'>-></span> <span class='conid'>ChildNodes</span>
<a name="line-147"></a> <span class='varid'>filterNodeSet</span>
<a name="line-148"></a> <span class='keyglyph'>=</span> <span class='varid'>concat</span> <span class='varop'>.</span> <span class='varid'>zipWith</span> <span class='varid'>filterIx</span> <span class='keyglyph'>[</span><span class='num'>0</span><span class='keyglyph'>..</span><span class='keyglyph'>]</span>
<a name="line-149"></a>
<a name="line-150"></a> <span class='varid'>filterIx</span> <span class='keyglyph'>::</span> <span class='conid'>Int</span> <span class='keyglyph'>-></span> <span class='conid'>XmlNodeSet</span> <span class='keyglyph'>-></span> <span class='conid'>ChildNodes</span>
<a name="line-151"></a> <span class='varid'>filterIx</span> <span class='sel'>_ix</span> <span class='layout'>(</span><span class='conid'>XNS</span> <span class='conid'>False</span> <span class='conid'>[]</span> <span class='conid'>[]</span><span class='layout'>)</span>
<a name="line-152"></a> <span class='keyglyph'>=</span> <span class='conid'>[]</span>
<a name="line-153"></a> <span class='varid'>filterIx</span> <span class='varid'>ix</span> <span class='varid'>ps</span>
<a name="line-154"></a> <span class='keyglyph'>=</span> <span class='keyglyph'>[</span><span class='layout'>(</span><span class='varid'>ix</span><span class='layout'>,</span> <span class='varid'>ps</span><span class='layout'>)</span><span class='keyglyph'>]</span>
<a name="line-155"></a>
<a name="line-156"></a><span class='comment'>-- |</span>
<a name="line-157"></a><span class='comment'>-- compute a node set from a tree, containing all nodes selected by the predicate arrow</span>
<a name="line-158"></a><span class='comment'>--</span>
<a name="line-159"></a><span class='comment'>-- computation of the set of element nodes with name \"a\" is done with</span>
<a name="line-160"></a><span class='comment'>--</span>
<a name="line-161"></a><span class='comment'>-- > getElemNodeSet (hasName "a")</span>
<a name="line-162"></a>
<a name="line-163"></a><a name="getElemNodeSet"></a><span class='definition'>getElemNodeSet</span> <span class='keyglyph'>::</span> <span class='conid'>ArrowXml</span> <span class='varid'>a</span> <span class='keyglyph'>=></span> <span class='varid'>a</span> <span class='conid'>XmlTree</span> <span class='conid'>XmlTree</span> <span class='keyglyph'>-></span> <span class='varid'>a</span> <span class='conid'>XmlTree</span> <span class='conid'>XmlNodeSet</span>
<a name="line-164"></a><span class='definition'>getElemNodeSet</span> <span class='varid'>f</span>
<a name="line-165"></a> <span class='keyglyph'>=</span> <span class='varid'>getNodeSet</span> <span class='varid'>none</span> <span class='varid'>f</span>
<a name="line-166"></a>
<a name="line-167"></a><span class='comment'>-- |</span>
<a name="line-168"></a><span class='comment'>-- compute a node set from a tree, containing all nodes including attribute nodes</span>
<a name="line-169"></a><span class='comment'>-- elected by the predicate arrow</span>
<a name="line-170"></a>
<a name="line-171"></a><a name="getElemAndAttrNodeSet"></a><span class='definition'>getElemAndAttrNodeSet</span> <span class='keyglyph'>::</span> <span class='conid'>ArrowXml</span> <span class='varid'>a</span> <span class='keyglyph'>=></span> <span class='varid'>a</span> <span class='conid'>XmlTree</span> <span class='conid'>XmlTree</span> <span class='keyglyph'>-></span> <span class='varid'>a</span> <span class='conid'>XmlTree</span> <span class='conid'>XmlNodeSet</span>
<a name="line-172"></a><span class='definition'>getElemAndAttrNodeSet</span> <span class='varid'>f</span>
<a name="line-173"></a> <span class='keyglyph'>=</span> <span class='varid'>getNodeSet</span> <span class='layout'>(</span> <span class='varid'>getAttrl</span>
<a name="line-174"></a> <span class='varop'>>>></span>
<a name="line-175"></a> <span class='layout'>(</span> <span class='varid'>f</span> <span class='varop'>`guards`</span> <span class='varid'>getAttrName</span> <span class='layout'>)</span>
<a name="line-176"></a> <span class='layout'>)</span> <span class='varid'>f</span>
<a name="line-177"></a>
<a name="line-178"></a><span class='comment'>-- ------------------------------------------------------------</span>
<a name="line-179"></a>
<a name="line-180"></a><span class='comment'>-- |</span>
<a name="line-181"></a><span class='comment'>-- select all subtrees specified by a previously computed node set</span>
<a name="line-182"></a><span class='comment'>--</span>
<a name="line-183"></a><span class='comment'>-- the following law holds:</span>
<a name="line-184"></a><span class='comment'>--</span>
<a name="line-185"></a><span class='comment'>-- > getFromNodeSet $< getElemNodeSet f == multi f</span>
<a name="line-186"></a>
<a name="line-187"></a><a name="getFromNodeSet"></a><span class='definition'>getFromNodeSet</span> <span class='keyglyph'>::</span> <span class='conid'>ArrowXml</span> <span class='varid'>a</span> <span class='keyglyph'>=></span> <span class='conid'>XmlNodeSet</span> <span class='keyglyph'>-></span> <span class='varid'>a</span> <span class='conid'>XmlTree</span> <span class='conid'>XmlTree</span>
<a name="line-188"></a><span class='definition'>getFromNodeSet</span> <span class='layout'>(</span><span class='conid'>XNS</span> <span class='varid'>t</span> <span class='varid'>al</span> <span class='varid'>cl</span><span class='layout'>)</span>
<a name="line-189"></a> <span class='keyglyph'>=</span> <span class='varid'>fromLA</span> <span class='varop'>$</span>
<a name="line-190"></a> <span class='layout'>(</span> <span class='keyword'>if</span> <span class='varid'>t</span> <span class='keyword'>then</span> <span class='varid'>this</span> <span class='keyword'>else</span> <span class='varid'>none</span> <span class='layout'>)</span>
<a name="line-191"></a> <span class='varop'><+></span>
<a name="line-192"></a> <span class='layout'>(</span> <span class='varid'>getAttrl</span> <span class='varop'>>>></span> <span class='varid'>getFromAttrl</span> <span class='varid'>al</span> <span class='layout'>)</span>
<a name="line-193"></a> <span class='varop'><+></span>
<a name="line-194"></a> <span class='layout'>(</span> <span class='varid'>getFromChildren</span> <span class='layout'>(</span><span class='num'>0</span><span class='comment'>-</span><span class='num'>1</span><span class='layout'>)</span> <span class='varid'>cl</span> <span class='varop'>$<</span> <span class='varid'>listA</span> <span class='varid'>getChildren</span> <span class='layout'>)</span>
<a name="line-195"></a> <span class='keyword'>where</span>
<a name="line-196"></a>
<a name="line-197"></a> <span class='varid'>getFromAttrl</span> <span class='keyglyph'>::</span> <span class='keyglyph'>[</span><span class='conid'>QName</span><span class='keyglyph'>]</span> <span class='keyglyph'>-></span> <span class='conid'>LA</span> <span class='conid'>XmlTree</span> <span class='conid'>XmlTree</span>
<a name="line-198"></a> <span class='varid'>getFromAttrl</span> <span class='varid'>l</span>
<a name="line-199"></a> <span class='keyglyph'>=</span> <span class='layout'>(</span> <span class='varid'>catA</span> <span class='varop'>.</span> <span class='varid'>map</span> <span class='varid'>hasQName</span> <span class='varop'>$</span> <span class='varid'>l</span><span class='layout'>)</span>
<a name="line-200"></a> <span class='varop'>`guards`</span>
<a name="line-201"></a> <span class='varid'>this</span>
<a name="line-202"></a>
<a name="line-203"></a> <span class='varid'>getFromChildren</span> <span class='keyglyph'>::</span> <span class='conid'>Int</span> <span class='keyglyph'>-></span> <span class='conid'>ChildNodes</span> <span class='keyglyph'>-></span> <span class='conid'>XmlTrees</span> <span class='keyglyph'>-></span> <span class='conid'>LA</span> <span class='conid'>XmlTree</span> <span class='conid'>XmlTree</span>
<a name="line-204"></a> <span class='varid'>getFromChildren</span> <span class='keyword'>_</span> <span class='conid'>[]</span> <span class='keyword'>_</span>
<a name="line-205"></a> <span class='keyglyph'>=</span> <span class='varid'>none</span>
<a name="line-206"></a>
<a name="line-207"></a> <span class='varid'>getFromChildren</span> <span class='varid'>i'</span> <span class='layout'>(</span><span class='layout'>(</span><span class='varid'>i</span><span class='layout'>,</span> <span class='varid'>sp</span><span class='layout'>)</span> <span class='conop'>:</span> <span class='varid'>sps</span><span class='layout'>)</span> <span class='varid'>ts</span>
<a name="line-208"></a> <span class='keyglyph'>=</span> <span class='layout'>(</span> <span class='varid'>arrL</span> <span class='layout'>(</span><span class='varid'>const</span> <span class='varid'>t'</span><span class='layout'>)</span> <span class='varop'>>>></span> <span class='varid'>getFromNodeSet</span> <span class='varid'>sp</span> <span class='layout'>)</span>
<a name="line-209"></a> <span class='varop'><+></span>
<a name="line-210"></a> <span class='varid'>getFromChildren</span> <span class='varid'>i</span> <span class='varid'>sps</span> <span class='varid'>ts'</span>
<a name="line-211"></a> <span class='keyword'>where</span>
<a name="line-212"></a> <span class='layout'>(</span><span class='varid'>t'</span><span class='layout'>,</span> <span class='varid'>ts'</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>splitAt</span> <span class='num'>1</span> <span class='varop'>.</span> <span class='varid'>drop</span> <span class='layout'>(</span><span class='varid'>i</span><span class='comment'>-</span><span class='varid'>i'</span><span class='comment'>-</span><span class='num'>1</span><span class='layout'>)</span> <span class='varop'>$</span> <span class='varid'>ts</span>
<a name="line-213"></a>
<a name="line-214"></a><span class='comment'>-- ------------------------------------------------------------</span>
<a name="line-215"></a>
<a name="line-216"></a><span class='comment'>-- |</span>
<a name="line-217"></a><span class='comment'>-- process all subtrees selected by an XPath expression</span>
<a name="line-218"></a><span class='comment'>--</span>
<a name="line-219"></a><span class='comment'>-- the following law holds:</span>
<a name="line-220"></a><span class='comment'>--</span>
<a name="line-221"></a><span class='comment'>-- > processXPathTrees p xpathExpr == processFromNodeSet p $< getXPathNodeSet xpathExpr</span>
<a name="line-222"></a>
<a name="line-223"></a>
<a name="line-224"></a><a name="processXPathTrees"></a><span class='definition'>processXPathTrees</span> <span class='keyglyph'>::</span> <span class='conid'>ArrowXml</span> <span class='varid'>a</span> <span class='keyglyph'>=></span> <span class='varid'>a</span> <span class='conid'>XmlTree</span> <span class='conid'>XmlTree</span> <span class='keyglyph'>-></span> <span class='conid'>String</span> <span class='keyglyph'>-></span> <span class='varid'>a</span> <span class='conid'>XmlTree</span> <span class='conid'>XmlTree</span>
<a name="line-225"></a><span class='definition'>processXPathTrees</span> <span class='varid'>f</span> <span class='keyglyph'>=</span> <span class='varid'>processXPathTreesWithNsEnv</span> <span class='varid'>f</span> <span class='conid'>[]</span>
<a name="line-226"></a>
<a name="line-227"></a><span class='comment'>-- | Same as 'processXPathTrees' but with namespace environment for the XPath names</span>
<a name="line-228"></a>
<a name="line-229"></a><a name="processXPathTreesWithNsEnv"></a><span class='definition'>processXPathTreesWithNsEnv</span> <span class='keyglyph'>::</span> <span class='conid'>ArrowXml</span> <span class='varid'>a</span> <span class='keyglyph'>=></span> <span class='varid'>a</span> <span class='conid'>XmlTree</span> <span class='conid'>XmlTree</span> <span class='keyglyph'>-></span> <span class='conid'>Attributes</span> <span class='keyglyph'>-></span> <span class='conid'>String</span> <span class='keyglyph'>-></span> <span class='varid'>a</span> <span class='conid'>XmlTree</span> <span class='conid'>XmlTree</span>
<a name="line-230"></a><span class='definition'>processXPathTreesWithNsEnv</span> <span class='varid'>f</span> <span class='varid'>nsEnv</span> <span class='varid'>query</span>
<a name="line-231"></a> <span class='keyglyph'>=</span> <span class='varid'>choiceA</span>
<a name="line-232"></a> <span class='keyglyph'>[</span> <span class='varid'>isRoot</span> <span class='conop'>:-></span> <span class='varid'>processChildren</span> <span class='varid'>pns</span>
<a name="line-233"></a> <span class='layout'>,</span> <span class='varid'>this</span> <span class='conop'>:-></span> <span class='varid'>pns</span>
<a name="line-234"></a> <span class='keyglyph'>]</span>
<a name="line-235"></a> <span class='keyword'>where</span>
<a name="line-236"></a> <span class='varid'>pns</span> <span class='keyglyph'>=</span> <span class='varid'>processFromNodeSet</span> <span class='varid'>f</span> <span class='varop'>$<</span> <span class='varid'>getXPathNodeSetWithNsEnv</span> <span class='varid'>nsEnv</span> <span class='varid'>query</span>
<a name="line-237"></a>
<a name="line-238"></a><span class='comment'>-- |</span>
<a name="line-239"></a><span class='comment'>-- process all subtrees specified by a previously computed node set in bottom up manner</span>
<a name="line-240"></a><span class='comment'>--</span>
<a name="line-241"></a><span class='comment'>-- the follwoing law holds:</span>
<a name="line-242"></a><span class='comment'>--</span>
<a name="line-243"></a><span class='comment'>-- > processFromNodeSet g $< getElemNodeSet f == processBottomUp (g `when` f)</span>
<a name="line-244"></a><span class='comment'>--</span>
<a name="line-245"></a><span class='comment'>-- when attributes are contained in the node set (see 'getElemAndAttrNodeSet'), these are processed</span>
<a name="line-246"></a><span class='comment'>-- after the children and before the node itself</span>
<a name="line-247"></a><span class='comment'>--</span>
<a name="line-248"></a><span class='comment'>-- the advantage of processFromNodeSet is the separation of the selection of set of nodes to be processed (e.g. modified)</span>
<a name="line-249"></a><span class='comment'>-- from the real proccessing. The selection sometimes can be done once, the processing possibly many times.</span>
<a name="line-250"></a>
<a name="line-251"></a><a name="processFromNodeSet"></a><span class='definition'>processFromNodeSet</span> <span class='keyglyph'>::</span> <span class='conid'>ArrowXml</span> <span class='varid'>a</span> <span class='keyglyph'>=></span> <span class='varid'>a</span> <span class='conid'>XmlTree</span> <span class='conid'>XmlTree</span> <span class='keyglyph'>-></span> <span class='conid'>XmlNodeSet</span> <span class='keyglyph'>-></span> <span class='varid'>a</span> <span class='conid'>XmlTree</span> <span class='conid'>XmlTree</span>
<a name="line-252"></a><span class='definition'>processFromNodeSet</span> <span class='varid'>f</span> <span class='layout'>(</span><span class='conid'>XNS</span> <span class='varid'>t</span> <span class='varid'>al</span> <span class='varid'>cl</span><span class='layout'>)</span>
<a name="line-253"></a> <span class='keyglyph'>=</span> <span class='layout'>(</span> <span class='keyword'>if</span> <span class='varid'>null</span> <span class='varid'>cl</span>
<a name="line-254"></a> <span class='keyword'>then</span> <span class='varid'>this</span>
<a name="line-255"></a> <span class='keyword'>else</span> <span class='varid'>replaceChildren</span> <span class='layout'>(</span> <span class='varid'>processC</span> <span class='layout'>(</span><span class='num'>0</span><span class='comment'>-</span><span class='num'>1</span><span class='layout'>)</span> <span class='varid'>cl</span> <span class='varop'>$<</span> <span class='varid'>listA</span> <span class='varid'>getChildren</span> <span class='layout'>)</span>
<a name="line-256"></a> <span class='layout'>)</span>
<a name="line-257"></a> <span class='varop'>>>></span>
<a name="line-258"></a> <span class='layout'>(</span> <span class='keyword'>if</span> <span class='varid'>null</span> <span class='varid'>al</span>
<a name="line-259"></a> <span class='keyword'>then</span> <span class='varid'>this</span>
<a name="line-260"></a> <span class='keyword'>else</span> <span class='varid'>processAttrl</span> <span class='layout'>(</span><span class='varid'>processA</span> <span class='varid'>al</span><span class='layout'>)</span>
<a name="line-261"></a> <span class='layout'>)</span>
<a name="line-262"></a> <span class='varop'>>>></span>
<a name="line-263"></a> <span class='layout'>(</span> <span class='keyword'>if</span> <span class='varid'>not</span> <span class='varid'>t</span>
<a name="line-264"></a> <span class='keyword'>then</span> <span class='varid'>this</span>
<a name="line-265"></a> <span class='keyword'>else</span> <span class='varid'>f</span>
<a name="line-266"></a> <span class='layout'>)</span>
<a name="line-267"></a> <span class='keyword'>where</span>
<a name="line-268"></a>
<a name="line-269"></a> <span class='comment'>-- processA :: ChildNodes -> a XmlTree XmlTree</span>
<a name="line-270"></a> <span class='varid'>processA</span> <span class='varid'>l</span>
<a name="line-271"></a> <span class='keyglyph'>=</span> <span class='varid'>f</span> <span class='varop'>`when`</span> <span class='layout'>(</span> <span class='varid'>catA</span> <span class='varop'>.</span> <span class='varid'>map</span> <span class='varid'>hasQName</span> <span class='varop'>$</span> <span class='varid'>l</span><span class='layout'>)</span>
<a name="line-272"></a>
<a name="line-273"></a> <span class='comment'>-- processC :: ChildNodes -> XmlTrees -> a XmlTree XmlTree</span>
<a name="line-274"></a> <span class='varid'>processC</span> <span class='keyword'>_</span> <span class='conid'>[]</span> <span class='varid'>ts</span>
<a name="line-275"></a> <span class='keyglyph'>=</span> <span class='varid'>arrL</span> <span class='layout'>(</span><span class='varid'>const</span> <span class='varid'>ts</span><span class='layout'>)</span>
<a name="line-276"></a>
<a name="line-277"></a> <span class='varid'>processC</span> <span class='varid'>i'</span> <span class='layout'>(</span><span class='layout'>(</span><span class='varid'>i</span><span class='layout'>,</span> <span class='varid'>sp</span><span class='layout'>)</span> <span class='conop'>:</span> <span class='varid'>sps</span><span class='layout'>)</span> <span class='varid'>ts</span>
<a name="line-278"></a> <span class='keyglyph'>=</span> <span class='varid'>arrL</span> <span class='layout'>(</span><span class='varid'>const</span> <span class='varid'>ts1</span><span class='layout'>)</span>
<a name="line-279"></a> <span class='varop'><+></span>
<a name="line-280"></a> <span class='layout'>(</span> <span class='varid'>arrL</span> <span class='layout'>(</span><span class='varid'>const</span> <span class='varid'>ti</span><span class='layout'>)</span> <span class='varop'>>>></span> <span class='varid'>processFromNodeSet</span> <span class='varid'>f</span> <span class='varid'>sp</span><span class='layout'>)</span>
<a name="line-281"></a> <span class='varop'><+></span>
<a name="line-282"></a> <span class='varid'>processC</span> <span class='varid'>i</span> <span class='varid'>sps</span> <span class='varid'>ts21</span>
<a name="line-283"></a> <span class='keyword'>where</span>
<a name="line-284"></a> <span class='layout'>(</span><span class='varid'>ts1</span><span class='layout'>,</span> <span class='varid'>ts2</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>splitAt</span> <span class='layout'>(</span><span class='varid'>i</span><span class='comment'>-</span><span class='varid'>i'</span><span class='comment'>-</span><span class='num'>1</span><span class='layout'>)</span> <span class='varid'>ts</span>
<a name="line-285"></a> <span class='layout'>(</span><span class='varid'>ti</span><span class='layout'>,</span> <span class='varid'>ts21</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>splitAt</span> <span class='num'>1</span> <span class='varid'>ts2</span>
<a name="line-286"></a>
<a name="line-287"></a><span class='comment'>-- ------------------------------------------------------------</span>
</pre></body>
</html>