Revamped transformation layout to remove need for the "01_files" level

* "01_files" contained a single "source" transformation which listed the contents of the "00_content" level
** this was unnecessary as the base "list" transformation already lists the contents of all levels
* added new "expression" mode to datasource meta tag processing in the task processing transformation
** this expression modes allows for the evaluation of arbitrary XPath statements
*** e.g. a query to the results of "list.xsl"
* modified base transformation datasource structures to include the level and meta tree
* modified all existing content transformations to query the level-tree instead of the deprecated "source.xml"
** i.e. XPath statements
** the main change is that directories are available as "directory" nodes instead of nodes named by the directory name
* these changes where implemented to simplify the architecture and to increase flexibility

1 files changed, 41 insertions, 0 deletions

diff --git a/source/02_meta/articles.xsl b/source/02_meta/articles.xsl
new file mode 100644
index 0000000..1a8b8fa
--- /dev/null
+++ b/source/02_meta/articles.xsl
@@ -0,0 +1,41 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<xsl:stylesheet
+	version="1.0"
+	xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+>
+
+<xsl:include href="[utility/datasource.xsl]"/>
+
+<xsl:variable name="meta">
+	<datasource type="main"  mode="full" source="01_data/articles.xml" target="articles"/>
+	<target     mode="plain" value="articles.xml"/> 
+</xsl:variable>
+
+<xsl:key name="years" match="datasource/articles/entry/date/year/text()" use="." />
+
+<xsl:template match="articles">
+	<xsl:for-each select="entry/date/year/text()[generate-id() = generate-id(key('years',.)[1])]">
+		<entry handle="{.}">
+			<xsl:call-template name="get_articles">
+				<xsl:with-param name="year" select="."/>
+			</xsl:call-template>
+		</entry>
+	</xsl:for-each>
+</xsl:template>
+
+<xsl:template name="get_articles">
+	<xsl:param name="year"/>
+
+	<xsl:for-each select="/datasource/articles/entry[date/year = $year]">
+		<article handle="{@handle}">
+			<title>
+				<xsl:value-of select="title"/>
+			</title>
+			<date>
+				<xsl:value-of select="date/full"/>
+			</date>
+		</article>
+	</xsl:for-each>
+</xsl:template>
+
+</xsl:stylesheet>