hxt-8.0.0: doc/hdoc/src/Text-XML-HXT-Parser-HtmlParser.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.Parser.HtmlParser
<a name="line-5"></a> Copyright : Copyright (C) 2005 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 : stable
<a name="line-10"></a> Portability: portable
<a name="line-11"></a>
<a name="line-12"></a> This parser tries to interprete everything as HTML
<a name="line-13"></a> no errors are emitted during parsing. If something looks
<a name="line-14"></a> weired, warning messages are inserted in the document tree.
<a name="line-15"></a>
<a name="line-16"></a> Module contains state filter for easy parsing and error handling
<a name="line-17"></a> real work is done in 'Text.XML.HXT.Parser.HtmlParsec'
<a name="line-18"></a>
<a name="line-19"></a>-}</span>
<a name="line-20"></a>
<a name="line-21"></a><span class='comment'>-- ------------------------------------------------------------</span>
<a name="line-22"></a>
<a name="line-23"></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'>Parser</span><span class='varop'>.</span><span class='conid'>HtmlParser</span>
<a name="line-24"></a> <span class='layout'>(</span> <span class='varid'>getHtmlDoc</span>
<a name="line-25"></a> <span class='layout'>,</span> <span class='varid'>parseHtmlDoc</span>
<a name="line-26"></a> <span class='layout'>,</span> <span class='varid'>runHtmlParser</span>
<a name="line-27"></a> <span class='layout'>,</span> <span class='varid'>substHtmlEntities</span>
<a name="line-28"></a> <span class='layout'>,</span> <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'>Parser</span><span class='varop'>.</span><span class='conid'>HtmlParsec</span>
<a name="line-29"></a> <span class='layout'>)</span>
<a name="line-30"></a>
<a name="line-31"></a><span class='keyword'>where</span>
<a name="line-32"></a>
<a name="line-33"></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'>XmlTree</span>
<a name="line-34"></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'>XmlState</span>
<a name="line-35"></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'>Parser</span><span class='varop'>.</span><span class='conid'>HtmlParsec</span>
<a name="line-36"></a>
<a name="line-37"></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'>Parser</span><span class='varop'>.</span><span class='conid'>XmlInput</span>
<a name="line-38"></a> <span class='layout'>(</span> <span class='varid'>getXmlContents</span>
<a name="line-39"></a> <span class='layout'>)</span>
<a name="line-40"></a>
<a name="line-41"></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'>Parser</span><span class='varop'>.</span><span class='conid'>XmlOutput</span>
<a name="line-42"></a> <span class='layout'>(</span> <span class='varid'>traceTree</span>
<a name="line-43"></a> <span class='layout'>,</span> <span class='varid'>traceSource</span>
<a name="line-44"></a> <span class='layout'>,</span> <span class='varid'>traceMsg</span>
<a name="line-45"></a> <span class='layout'>)</span>
<a name="line-46"></a>
<a name="line-47"></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'>Parser</span><span class='varop'>.</span><span class='conid'>XhtmlEntities</span>
<a name="line-48"></a> <span class='layout'>(</span> <span class='varid'>xhtmlEntities</span>
<a name="line-49"></a> <span class='layout'>)</span>
<a name="line-50"></a>
<a name="line-51"></a><span class='comment'>-- ------------------------------------------------------------</span>
<a name="line-52"></a>
<a name="line-53"></a><span class='comment'>-- |</span>
<a name="line-54"></a><span class='comment'>-- read a document and parse it with 'parseHtmlDoc'. The main entry point of this module</span>
<a name="line-55"></a><span class='comment'>--</span>
<a name="line-56"></a><span class='comment'>-- The input tree must be a root tree like in ' Text.XML.HXT.Parser.MainFunctions.getXmlDoc'. The content is read with 'Text.XML.HXT.Parser.XmlInput.getXmlContents',</span>
<a name="line-57"></a><span class='comment'>-- is parsed with 'parseHtmlDoc' and canonicalized (char refs are substituted in content and attributes,</span>
<a name="line-58"></a><span class='comment'>-- but comment is preserved)</span>
<a name="line-59"></a><span class='comment'>--</span>
<a name="line-60"></a><span class='comment'>-- see also : 'Text.XML.HXT.Parser.DTDProcessing.getWellformedDoc'</span>
<a name="line-61"></a>
<a name="line-62"></a><a name="getHtmlDoc"></a><span class='definition'>getHtmlDoc</span> <span class='keyglyph'>::</span> <span class='conid'>XmlStateFilter</span> <span class='varid'>state</span>
<a name="line-63"></a><span class='definition'>getHtmlDoc</span>
<a name="line-64"></a> <span class='keyglyph'>=</span> <span class='varid'>setSystemParams</span>
<a name="line-65"></a> <span class='varop'>.>></span>
<a name="line-66"></a> <span class='varid'>getXmlContents</span>
<a name="line-67"></a> <span class='varop'>.>></span>
<a name="line-68"></a> <span class='varid'>parseHtmlDoc</span>
<a name="line-69"></a>
<a name="line-70"></a><span class='comment'>-- | The HTML parsing filter</span>
<a name="line-71"></a><span class='comment'>--</span>
<a name="line-72"></a><span class='comment'>-- The input is parsed with 'runHtmlParser', everything is interpreted as HTML,</span>
<a name="line-73"></a><span class='comment'>-- if errors ocuur, the parser will try to do some meaningfull action and continues</span>
<a name="line-74"></a><span class='comment'>-- parsing. Afterwards the entitiy references for defined for XHTML are resovled,</span>
<a name="line-75"></a><span class='comment'>-- any unresolved reference is transformed into plain text.</span>
<a name="line-76"></a><span class='comment'>--</span>
<a name="line-77"></a><span class='comment'>-- Error messages</span>
<a name="line-78"></a><span class='comment'>-- during parsing and entity resolving are added as warning nodes into the resulting tree.</span>
<a name="line-79"></a><span class='comment'>--</span>
<a name="line-80"></a><span class='comment'>-- The warnings are issued, if the 1. parameter noWarnings is set to True,</span>
<a name="line-81"></a><span class='comment'>-- afterwards all are removed from the resulting tree.</span>
<a name="line-82"></a>
<a name="line-83"></a><a name="parseHtmlDoc"></a><span class='definition'>parseHtmlDoc</span> <span class='keyglyph'>::</span> <span class='conid'>XmlStateFilter</span> <span class='varid'>a</span>
<a name="line-84"></a><span class='definition'>parseHtmlDoc</span>
<a name="line-85"></a> <span class='keyglyph'>=</span> <span class='varid'>parseDoc</span>
<a name="line-86"></a> <span class='varop'>`whenM`</span> <span class='layout'>(</span> <span class='varid'>isRoot</span> <span class='varop'>.></span> <span class='varid'>getChildren</span> <span class='varop'>.></span> <span class='varid'>isXText</span> <span class='layout'>)</span>
<a name="line-87"></a> <span class='keyword'>where</span>
<a name="line-88"></a> <span class='varid'>parseDoc</span> <span class='varid'>t'</span>
<a name="line-89"></a> <span class='keyglyph'>=</span> <span class='layout'>(</span> <span class='varid'>traceMsg</span> <span class='num'>2</span> <span class='layout'>(</span><span class='str'>"parseHtmlDoc: parse HTML document "</span> <span class='varop'>++</span> <span class='varid'>show</span> <span class='varid'>loc</span><span class='layout'>)</span>
<a name="line-90"></a> <span class='varop'>.>></span>
<a name="line-91"></a> <span class='varid'>runHtmlParser</span>
<a name="line-92"></a> <span class='varop'>.>></span>
<a name="line-93"></a> <span class='varid'>liftMf</span> <span class='layout'>(</span><span class='varid'>processTopDown</span> <span class='varid'>substHtmlEntities</span><span class='layout'>)</span>
<a name="line-94"></a> <span class='varop'>.>></span>
<a name="line-95"></a> <span class='varid'>removeWarnings</span>
<a name="line-96"></a> <span class='varop'>.>></span>
<a name="line-97"></a> <span class='varid'>traceTree</span>
<a name="line-98"></a> <span class='varop'>.>></span>
<a name="line-99"></a> <span class='varid'>traceSource</span>
<a name="line-100"></a> <span class='layout'>)</span> <span class='varop'>$</span> <span class='varid'>t'</span>
<a name="line-101"></a> <span class='keyword'>where</span>
<a name="line-102"></a> <span class='varid'>loc</span> <span class='keyglyph'>=</span> <span class='varid'>valueOf</span> <span class='varid'>a_source</span> <span class='varid'>t'</span> <span class='comment'>-- get document source uri</span>
<a name="line-103"></a>
<a name="line-104"></a> <span class='varid'>removeWarnings</span> <span class='keyglyph'>::</span> <span class='conid'>XmlStateFilter</span> <span class='varid'>a</span>
<a name="line-105"></a> <span class='varid'>removeWarnings</span> <span class='varid'>t'</span>
<a name="line-106"></a> <span class='keyglyph'>=</span> <span class='keyword'>let</span>
<a name="line-107"></a> <span class='varid'>noWarnings</span> <span class='keyglyph'>=</span> <span class='varid'>not</span> <span class='layout'>(</span><span class='varid'>satisfies</span> <span class='layout'>(</span><span class='varid'>hasOption</span> <span class='varid'>a_issue_warnings</span><span class='layout'>)</span> <span class='varid'>t'</span><span class='layout'>)</span>
<a name="line-108"></a> <span class='varid'>selWarnings</span> <span class='keyglyph'>=</span> <span class='varid'>deep</span>
<a name="line-109"></a> <span class='layout'>(</span> <span class='varid'>choice</span> <span class='keyglyph'>[</span> <span class='varid'>isWarning</span> <span class='conop'>:-></span> <span class='varid'>this</span>
<a name="line-110"></a> <span class='layout'>,</span> <span class='varid'>isXTag</span> <span class='conop'>:-></span> <span class='layout'>(</span><span class='varid'>getAttrl</span> <span class='varop'>.></span> <span class='varid'>selWarnings</span><span class='layout'>)</span>
<a name="line-111"></a> <span class='keyglyph'>]</span>
<a name="line-112"></a> <span class='layout'>)</span>
<a name="line-113"></a> <span class='varid'>remWarnings</span> <span class='keyglyph'>=</span> <span class='varid'>processTopDown</span>
<a name="line-114"></a> <span class='layout'>(</span> <span class='varid'>choice</span> <span class='keyglyph'>[</span> <span class='varid'>isWarning</span> <span class='conop'>:-></span> <span class='varid'>none</span>
<a name="line-115"></a> <span class='layout'>,</span> <span class='varid'>isXTag</span> <span class='conop'>:-></span> <span class='layout'>(</span><span class='varid'>processAttrl</span> <span class='layout'>(</span><span class='varid'>remWarnings</span> <span class='varop'>$$</span><span class='layout'>)</span><span class='layout'>)</span>
<a name="line-116"></a> <span class='layout'>,</span> <span class='varid'>this</span> <span class='conop'>:-></span> <span class='varid'>this</span>
<a name="line-117"></a> <span class='keyglyph'>]</span>
<a name="line-118"></a> <span class='layout'>)</span>
<a name="line-119"></a> <span class='varid'>warnings</span> <span class='keyglyph'>=</span> <span class='varid'>selWarnings</span> <span class='varid'>t'</span>
<a name="line-120"></a> <span class='keyword'>in</span> <span class='keyword'>do</span>
<a name="line-121"></a> <span class='keyword'>if</span> <span class='varid'>null</span> <span class='varid'>warnings</span>
<a name="line-122"></a> <span class='keyword'>then</span> <span class='varid'>thisM</span> <span class='varid'>t'</span>
<a name="line-123"></a> <span class='keyword'>else</span> <span class='keyword'>do</span>
<a name="line-124"></a> <span class='keyword'>if</span> <span class='varid'>noWarnings</span>
<a name="line-125"></a> <span class='keyword'>then</span> <span class='varid'>return</span> <span class='conid'>[]</span>
<a name="line-126"></a> <span class='keyword'>else</span> <span class='keyword'>do</span>
<a name="line-127"></a> <span class='varid'>issueError</span> <span class='varop'>$$<</span> <span class='varid'>warnings</span>
<a name="line-128"></a> <span class='varid'>return</span> <span class='layout'>(</span><span class='varid'>remWarnings</span> <span class='varid'>t'</span><span class='layout'>)</span>
<a name="line-129"></a>
<a name="line-130"></a><span class='comment'>-- | The pure HTML parser, usually called via 'parseHtmlDoc'.</span>
<a name="line-131"></a><span class='comment'>--</span>
<a name="line-132"></a>
<a name="line-133"></a><a name="runHtmlParser"></a><span class='definition'>runHtmlParser</span> <span class='keyglyph'>::</span> <span class='conid'>XmlStateFilter</span> <span class='varid'>a</span>
<a name="line-134"></a><span class='definition'>runHtmlParser</span> <span class='varid'>t</span>
<a name="line-135"></a> <span class='keyglyph'>=</span> <span class='keyword'>if</span> <span class='varid'>null</span> <span class='varid'>errs</span>
<a name="line-136"></a> <span class='keyword'>then</span> <span class='keyword'>do</span>
<a name="line-137"></a> <span class='varid'>return</span> <span class='layout'>(</span><span class='varid'>replaceChildren</span> <span class='varid'>res</span> <span class='varid'>t</span><span class='layout'>)</span>
<a name="line-138"></a> <span class='keyword'>else</span> <span class='keyword'>do</span>
<a name="line-139"></a> <span class='varid'>issueError</span> <span class='varop'>$$<</span> <span class='varid'>errs</span>
<a name="line-140"></a> <span class='varid'>return</span> <span class='layout'>(</span><span class='varid'>setStatus</span> <span class='varid'>c_err</span> <span class='str'>"parsing HTML"</span> <span class='varid'>t</span><span class='layout'>)</span>
<a name="line-141"></a> <span class='keyword'>where</span>
<a name="line-142"></a> <span class='varid'>res</span> <span class='keyglyph'>=</span> <span class='varid'>getChildren</span> <span class='varop'>.></span> <span class='varid'>parseHtmlText</span> <span class='varid'>loc</span> <span class='varop'>$</span> <span class='varid'>t</span>
<a name="line-143"></a> <span class='varid'>errs</span> <span class='keyglyph'>=</span> <span class='varid'>isXError</span> <span class='varop'>.></span> <span class='varid'>neg</span> <span class='varid'>isWarning</span> <span class='varop'>$$</span> <span class='varid'>res</span>
<a name="line-144"></a> <span class='varid'>loc</span> <span class='keyglyph'>=</span> <span class='varid'>valueOf</span> <span class='varid'>a_source</span> <span class='varid'>t</span>
<a name="line-145"></a>
<a name="line-146"></a>
<a name="line-147"></a><span class='comment'>-- ------------------------------------------------------------</span>
<a name="line-148"></a><span class='comment'>--</span>
<a name="line-149"></a><span class='comment'>-- XHTML entities</span>
<a name="line-150"></a>
<a name="line-151"></a><a name="substHtmlEntities"></a><span class='definition'>substHtmlEntities</span> <span class='keyglyph'>::</span> <span class='conid'>XmlTree</span> <span class='keyglyph'>-></span> <span class='conid'>XmlTrees</span>
<a name="line-152"></a><span class='definition'>substHtmlEntities</span>
<a name="line-153"></a> <span class='keyglyph'>=</span> <span class='varid'>choice</span> <span class='keyglyph'>[</span> <span class='varid'>isXEntityRef</span> <span class='conop'>:-></span> <span class='varid'>substEntity</span>
<a name="line-154"></a> <span class='layout'>,</span> <span class='varid'>isXTag</span> <span class='conop'>:-></span> <span class='varid'>processAttr</span> <span class='layout'>(</span><span class='varid'>processChildren</span> <span class='varid'>substHtmlEntities</span><span class='layout'>)</span>
<a name="line-155"></a> <span class='layout'>,</span> <span class='varid'>this</span> <span class='conop'>:-></span> <span class='varid'>this</span>
<a name="line-156"></a> <span class='keyglyph'>]</span>
<a name="line-157"></a> <span class='keyword'>where</span>
<a name="line-158"></a> <span class='varid'>substEntity</span> <span class='varid'>t'</span><span class='keyglyph'>@</span><span class='layout'>(</span><span class='conid'>NTree</span> <span class='layout'>(</span><span class='conid'>XEntityRef</span> <span class='varid'>en</span><span class='layout'>)</span> <span class='keyword'>_</span><span class='layout'>)</span>
<a name="line-159"></a> <span class='keyglyph'>=</span> <span class='keyword'>case</span> <span class='layout'>(</span><span class='varid'>lookup</span> <span class='varid'>en</span> <span class='varid'>xhtmlEntities</span><span class='layout'>)</span> <span class='keyword'>of</span>
<a name="line-160"></a> <span class='conid'>Just</span> <span class='varid'>i</span>
<a name="line-161"></a> <span class='keyglyph'>-></span> <span class='keyglyph'>[</span><span class='varid'>mkXCharRefTree</span> <span class='varid'>i</span><span class='keyglyph'>]</span>
<a name="line-162"></a> <span class='conid'>Nothing</span>
<a name="line-163"></a> <span class='keyglyph'>-></span> <span class='varid'>xwarn</span> <span class='layout'>(</span><span class='str'>"no XHTML entity found for reference: \"&"</span> <span class='varop'>++</span> <span class='varid'>en</span> <span class='varop'>++</span> <span class='str'>";\""</span><span class='layout'>)</span>
<a name="line-164"></a> <span class='varop'>++</span>
<a name="line-165"></a> <span class='layout'>(</span><span class='varid'>xmlTreesToText</span> <span class='keyglyph'>[</span><span class='varid'>t'</span><span class='keyglyph'>]</span><span class='layout'>)</span>
<a name="line-166"></a>
<a name="line-167"></a> <span class='varid'>substEntity</span> <span class='keyword'>_</span>
<a name="line-168"></a> <span class='keyglyph'>=</span> <span class='varid'>error</span> <span class='str'>"substHtmlEntities: illegal argument"</span>
<a name="line-169"></a>
<a name="line-170"></a><span class='comment'>-- ------------------------------------------------------------</span>
</pre></body>
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