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diff --git a/lib/xmerl/doc/src/xmerl_xs_examples.html b/lib/xmerl/doc/src/xmerl_xs_examples.html new file mode 100644 index 0000000000..aaa3bc5033 --- /dev/null +++ b/lib/xmerl/doc/src/xmerl_xs_examples.html @@ -0,0 +1,291 @@ + +<meta http-equiv="Context-Type" content="text/html; charset=iso-8859-1"> +<?xml version="1.0" encoding="iso-8859-1"?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" + "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd "> +<html xmlns="http://www.w3.org/1999/xhtml" ><head><title>XSLT like transformations in Erlang </title><style type="text/css"> body {margin-left:10%; margin-right:5%;} +.logo{float:right;} +.toc UL { + list-style-type: none; + border: solid; + border-width: thin; + padding-left: 10px; + padding-right: 10px; + padding-top: 5px; + padding-bottom: 5px; + background: #f0f0f0; + letter-spacing: 2px; + line-height: 20px; +} +</style></head><body> +<h3 id="sect_4.2">Examples</h3> + <hr /> + <h4>Example 1 Using xslapply</h4> + <p>original XSLT:</p> + <table border="1" cellspacing="0" cellpadding="5" width="100%" +bgcolor="#CCCCCC"><tr><td><pre><code> + + <xsl:template match="doc/title"> + <h1> + <xsl:apply-templates/> + </h1> + </xsl:template> + + </code></pre></td></tr></table> + <p> + becomes in Erlang:</p> + <table border="1" cellspacing="0" cellpadding="5" width="100%" +bgcolor="#CCCCCC"><tr><td><pre><code> + + template(E = #xmlElement{ parents=[{'doc',_}|_], name='title'}) -> + ["<h1>", + xslapply(fun template/1, E), + "</h1>"]; + + </code></pre></td></tr></table> + + <hr /> + <hr /> + <h4>Example 2 Using value_of and select</h4> + <table border="1" cellspacing="0" cellpadding="5" width="100%" +bgcolor="#CCCCCC"><tr><td><pre><code> + + <xsl:template match="title"> + <div align="center"><h1><xsl:value-of select="." /></h1></div> + </xsl:template> + + </code></pre></td></tr></table> + <p> + becomes: + </p> + <table border="1" cellspacing="0" cellpadding="5" width="100%" +bgcolor="#CCCCCC"><tr><td><pre><code> + +template(E = #xmlElement{name='title'}) -> + ["<div align=\"center\"><h1>", value_of(select(".", E)), "</h1></div>"]; + + </code></pre></td></tr></table> + <hr /> + <hr /> + <h4>Example 3 Simple xsl stylesheet</h4> +<p> + A complete example with the XSLT sheet in the xmerl distribution. +</p> + <table border="1" cellspacing="0" cellpadding="5" width="100%" +bgcolor="#CCCCCC"><tr><td><pre><code> + + +<xsl:stylesheet version="1.0" + xmlns:xsl="http://www.w3.org/1999/XSL/Transform" + xmlns="http://www.w3.org/TR/xhtml1/strict"> + + <xsl:strip-space elements="doc chapter section"/> + <xsl:output + method="xml" + indent="yes" + encoding="iso-8859-1" + /> + + <xsl:template match="doc"> + <html> + <head> + <title> + <xsl:value-of select="title"/> + </title> + </head> + <body> + <xsl:apply-templates/> + </body> + </html> + </xsl:template> + + <xsl:template match="doc/title"> + <h1> + <xsl:apply-templates/> + </h1> + </xsl:template> + + <xsl:template match="chapter/title"> + <h2> + <xsl:apply-templates/> + </h2> + </xsl:template> + + <xsl:template match="section/title"> + <h3> + <xsl:apply-templates/> + </h3> + </xsl:template> + + <xsl:template match="para"> + <p> + <xsl:apply-templates/> + </p> + </xsl:template> + + <xsl:template match="note"> + <p class="note"> + <b>NOTE: </b> + <xsl:apply-templates/> + </p> + </xsl:template> + + <xsl:template match="emph"> + <em> + <xsl:apply-templates/> + </em> + </xsl:template> + +</xsl:stylesheet> + + </code></pre></td></tr></table> + <hr /> + <hr /> + <h4>Example 4 Erlang version</h4> + <p> + Erlang transformation of previous example: + </p> + <table border="1" cellspacing="0" cellpadding="5" width="100%" +bgcolor="#CCCCCC"><tr><td><pre><code> + + +-include("xmerl.hrl"). + +-import(xmerl_xs, + [ xslapply/2, value_of/1, select/2, built_in_rules/2 ]). + +doctype()-> + "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Transitional//EN\"\ + \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd \">". + +process_xml(Doc)-> + template(Doc). + +template(E = #xmlElement{name='doc'})-> + [ "<\?xml version=\"1.0\" encoding=\"iso-8859-1\"\?>", + doctype(), + "<html xmlns=\"http://www.w3.org/1999/xhtml\" >" + "<head>" + "<title>", value_of(select("title",E)), "</title>" + "</head>" + "<body>", + xslapply( fun template/1, E), + "</body>" + "</html>" ]; + + +template(E = #xmlElement{ parents=[{'doc',_}|_], name='title'}) -> + ["<h1>", + xslapply( fun template/1, E), + "</h1>"]; + +template(E = #xmlElement{ parents=[{'chapter',_}|_], name='title'}) -> + ["<h2>", + xslapply( fun template/1, E), + "</h2>"]; + +template(E = #xmlElement{ parents=[{'section',_}|_], name='title'}) -> + ["<h3>", + xslapply( fun template/1, E), + "</h3>"]; + +template(E = #xmlElement{ name='para'}) -> + ["<p>", xslapply( fun template/1, E), "</p>"]; + +template(E = #xmlElement{ name='note'}) -> + ["<p class=\"note\">" + "<b>NOTE: </b>", + xslapply( fun template/1, E), + "</p>"]; + +template(E = #xmlElement{ name='emph'}) -> + ["<em>", xslapply( fun template/1, E), "</em>"]; + +template(E)-> + built_in_rules( fun template/1, E). + + </code></pre></td></tr></table> + <p> + It is important to end with a call to + <tt>xmerl_xs:built_in_rules/2</tt> + if you want any text to be written in "push" transforms. + That are the ones using a lot <tt>xslapply( fun + template/1, E )</tt> instead of + <tt>value_of(select("xpath",E))</tt>, + which is pull... + </p> + <hr /> +<p>The largest example is the stylesheet to transform this document + from the Simplified Docbook XML format to xhtml. The source + file is <tt>sdocbook2xhtml.erl</tt>. +</p> + + + <h3 id="sect_4.3">Tips and tricks</h3> + + <h4 id="sect_4.3.1">for-each</h4> + <p>The function for-each is quite common in XSLT stylesheets. + It can often be rewritten and replaced by select/1. Since + select/1 returns a list of #xmlElements and xslapply/2 + traverses them it is more or less the same as to loop over all + the elements. + </p> + + + <h4 id="sect_4.3.2">position()</h4> + <p>The XSLT position() and #xmlElement.pos are not the + same. One has to make an own position in Erlang.</p> + <hr /> + <h4>Example 5 Counting positions</h4> + <table border="1" cellspacing="0" cellpadding="5" width="100%" +bgcolor="#CCCCCC"><tr><td><pre><code> + +<xsl:template match="stanza"> + <p><xsl:apply-templates select="line" /></p> +</xsl:template> + +<xsl:template match="line"> + <xsl:if test="position() mod 2 = 0">&#160;&#160;</xsl:if> + <xsl:value-of select="." /><br /> +</xsl:template> + + </code></pre></td></tr></table> +<p>Can be written as</p> + <table border="1" cellspacing="0" cellpadding="5" width="100%" +bgcolor="#CCCCCC"><tr><td><pre><code> + +template(E = #xmlElement{name='stanza'}) -> + {Lines,LineNo} = lists:mapfoldl(fun template_pos/2, 1, select("line", E)), + ["<p>", Lines, "</p>"]. + +template_pos(E = #xmlElement{name='line'}, P) -> + {[indent_line(P rem 2), value_of(E#xmlElement.content), "<br />"], P + 1 }. + +indent_line(0)->"&#160;&#160;"; +indent_line(_)->"". + + </code></pre></td></tr></table> + <hr /> + + + <h4 id="sect_4.3.3">Global tree awareness</h4> + <p>In XSLT you have "root" access to the top of the tree + with XPath, even though you are somewhere deep in your + tree.</p> + <p>The xslapply/2 function only carries back the child part + of the tree to the template fun. But it is quite easy to write + template funs that handles both the child and top tree.</p> + <hr /> + <h4>Example 6 Passing the root tree</h4> + <p>The following example piece will prepend the article + title to any section title</p> + <table border="1" cellspacing="0" cellpadding="5" width="100%" +bgcolor="#CCCCCC"><tr><td><pre><code> + +template(E = #xmlElement{name='title'}, ETop ) -> + ["<h3>", value_of(select("title", ETop))," - ", + xslapply( fun(A) -> template(A, ETop) end, E), + "</h3>"]; + + </code></pre></td></tr></table> + <hr /> + </body></html>
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