<?xml version="1.0" encoding="UTF-8"?>

<!--

Relational pipes

Copyright © 2020 František Kučera (Frantovo.cz, GlobalCode.info)

This program is free software: you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation, version 3 of the License.

This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

GNU General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program. If not, see <http://www.gnu.org/licenses/>.

-->

<xsl:stylesheet version="1.0"

				xmlns="tag:globalcode.info,2018:relpipe"

				xmlns:sparql="http://www.w3.org/2005/sparql-results#"

				xmlns:xsl="http://www.w3.org/1999/XSL/Transform"

				xmlns:fn="http://www.w3.org/2005/xpath-functions"

				xmlns:xs="http://www.w3.org/2001/XMLSchema"

				exclude-result-prefixes="fn sparql xs">

	<xsl:output

		method="xml"

		indent="yes"

		encoding="UTF-8"/>

	<xsl:param name="relation" select="'rdf'"/>

	<xsl:template match="/sparql:sparql">

		<relpipe>

			<relation>

				<name>

					<xsl:value-of select="$relation"/>

				</name>

				<attributes-metadata>

					<xsl:for-each select="sparql:head/sparql:variable">

						<attribute-metadata name="{@name}" type="string"/>

						<!-- here we can optionally append additional attributes with some metadata -->

					</xsl:for-each>

				</attributes-metadata>

				<xsl:for-each select="sparql:results/sparql:result">

					<xsl:variable name="record" select="."/>

					<record>

						<xsl:for-each select="/sparql:sparql/sparql:head/sparql:variable">

							<xsl:variable name="attribute" select="@name"/>

							<xsl:call-template name="record">

								<xsl:with-param name="record" select="$record"/>

								<xsl:with-param name="attribute" select="$attribute"/>

							</xsl:call-template>

						</xsl:for-each>

					</record>

				</xsl:for-each>

			</relation>

		</relpipe>

	</xsl:template>

	<xsl:template name="record">

		<xsl:param name="record"/>

		<xsl:param name="attribute"/>

		<attribute>

			<xsl:value-of select="$record/sparql:binding[@name=$attribute]"/>

			<!-- here we can optionally append additional attributes with some metadata -->

			<!--

				<sparql:binding name="…attribute…">

					<sparql:uri>…value…</sparql:uri>

					<sparql:literal xml:lang="it">…value…</sparql:literal>

				</sparql:binding>

			-->

		</attribute>

	</xsl:template>

</xsl:stylesheet>