rng_to_dnf.xsl

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

<stylesheet version="2.0"
	xmlns="http://www.w3.org/1999/XSL/Transform"
	xmlns:rng="http://relaxng.org/ns/structure/1.0"
	xmlns:eoa="http://www.edition-open-access.de/ns"
	xmlns:xs="http://www.w3.org/2001/XMLSchema"
	exclude-result-prefixes="rng eoa xs"
>

	<template
		mode="rng_dnf_finish"
		match="rng:group"
	>
		<variable name="new_children" as="element()*">
			<for-each select="*">
				<choose>
					<!-- flatten nested groups -->
					<when test="self::rng:group">
						<variable name="sub_group">
							<apply-templates mode="rng_dnf_finish" select="."/>
						</variable>
						<copy-of select="$sub_group/*/*"/>
					</when>
					<!-- do not copy "rng:empty" elements: -->
					<when test="not(self::rng:empty)">
						<apply-templates mode="rng_dnf_finish" select="."/>
					</when>
				</choose>
			</for-each>
		</variable>
		<copy>
			<apply-templates mode="rng_dnf_finish" select="@*"/>
			<copy-of select="$new_children"/>
			<!-- if this is an empty group, write exactly ONE 'rng:empty' element -->
			<if test="count($new_children[not(self::rng:empty)]) = 0">
				<element name="empty" namespace="{$rng_namespace}"/>
			</if>
		</copy>
	</template>

	<!-- throw error, if there are any non-toplevel 'rng:choice' elements -->
	<template
		mode="rng_dnf_finish"
		match="rng:choice[not(parent::rng:element) and not(ancestor-or-self::rng:attribute)]"
	>
		<sequence select="eoa:error('rng_to_dnf', 'rng_dnf_finish: found choice which is not toplevel. (This indicates an internal error in the dnf calculation)')"/>
	</template>

	<template mode="rng_dnf_finish" match="@* | node()">
		<copy>
			<apply-templates mode="rng_dnf_finish" select="@* | node()"/>
		</copy>
	</template>

	<!-- replace "a?" ('rng:optional') by "(a | epsilon)" -->
	<template
		mode="rng_dnf_prepare"
		match="rng:optional"
	>
		<element name="choice" namespace="{$rng_namespace}">
			<choose>
				<when test="count(*) > 1">
					<element name="group" namespace="{$rng_namespace}">
						<copy-of select="*"/>
					</element>
				</when>
				<otherwise>
					<copy-of select="*"/>
				</otherwise>
			</choose>
			<element name="empty" namespace="{$rng_namespace}"/>
		</element>
	</template>

	<template mode="rng_dnf_prepare" match="@* | node()">
		<copy>
			<apply-templates mode="rng_dnf_prepare" select="@* | node()"/>
		</copy>
	</template>

	<!-- transform rng to "Disjunctive Normal Form" (DNF), e.g.:
		(a|b)c(d|e) -> (acd) | (bcd) | (ace) | (bce)
	-->
	<template
		mode="rng_to_dnf"
		match="rng:choice[not(ancestor-or-self::rng:attribute)]"
	>
		<param name="depth" as="xs:string" select="''"/>
		<variable name="normalized_children" as="element()*">
			<apply-templates mode="rng_to_dnf" select="*">
				<with-param name="depth" as="xs:string" select="concat($depth, ' ')"/>
			</apply-templates>
		</variable>
		<copy>
			<copy-of select="@*"/>
			<for-each select="$normalized_children[not(self::rng:choice or self::rng:optional)]">
				<copy-of select="."/>
			</for-each>
			<for-each select="$normalized_children[self::rng:choice]">
				<copy-of select="*"/>
			</for-each>
			<!--
			<for-each select="$normalized_children[self::rng:optional]">
				<copy-of select="*"/>
			</for-each>
			-->
		</copy>
	</template>

	<template
		mode="rng_to_dnf"
		match="*[not(ancestor-or-self::rng:attribute) and not(self::rng:define | self::rng:element | self::rng:choice)]"
	>
		<param name="depth" as="xs:string" select="''"/>
		<variable name="this" select="."/>
		<variable name="normalized_children" as="element()*">
			<apply-templates mode="rng_to_dnf" select="*">
				<with-param name="depth" as="xs:string" select="concat($depth, ' ')"/>
			</apply-templates>
		</variable>
		<choose>
			<when test="not($normalized_children[self::rng:choice])">
				<!-- debug output -->
				<sequence select="eoa:debug('rng_to_dnf', concat(
					$depth,
					'rng_to_dnf: ',
					parent::*/parent::*/name(), '/',
					parent::*/name(), '[', parent::*/position(), ']', '/',
					name(),'[',position(),']',
					' - just copy!'
				))"/>
				<copy>
					<copy-of select="@*"/>
					<copy-of select="$normalized_children"/>
					<copy-of select="text()"/>
				</copy>
			</when>
			<otherwise>
				<variable
					name="all_sub_choices_count"
					as="xs:integer*"
					select="
						for $i in $normalized_children[self::rng:choice or self::rng:optional] return (
							if ($i[self::rng:choice])
							then count( $i/* )
							else 2
						)
					"
				/>
				<variable
					name="all_sub_choices"
					as="xs:string*"
					select="eoa:all_seqs($all_sub_choices_count)" 
				/>
				<!-- debug output -->
				<sequence select="eoa:debug( 'rng_to_dnf', concat(
					$depth,
					'rng_to_dnf: ',
					parent::*/parent::*/name(), '/',
					parent::*/name(), '[', parent::*/position(), ']', '/',
					name(),'[',position(),']',
					' - children: ',
					string-join($normalized_children/name(), ','),
					' - all_sub_choices_count: ',
					string-join($all_sub_choices_count, ','),
					'. all_sub_choices: ',
					string-join($all_sub_choices, ',')
				))"/>
				<element name="choice" namespace="{$rng_namespace}">
					<for-each select="$all_sub_choices">
						<variable name="sub_choice"
							select="for $t in tokenize(.,' ') return xs:integer($t)"
							as="xs:integer*"
						/>
						<!-- debug output -->
						<call-template name="eoa:debug">
							<with-param name="module" select="'rng_to_dnf'"/>
							<with-param name="message">
								<text>current subchoice: </text>
								<value-of select="$sub_choice" separator=","/>
								<value-of select="$newline"/>
								<text>names: </text>
								<value-of select="$normalized_children/name()" separator=","/>
							</with-param>
						</call-template>
						<element name="group" namespace="{$rng_namespace}">
							<!--
							-->
							<call-template name="rng_to_dnf_helper">
								<with-param name="sub_elements" select="$normalized_children" as="element()*"/>
								<with-param name="choice_numbers" select="$sub_choice" as="xs:integer*"/>
							</call-template>
						</element>
					</for-each>
				</element>
			</otherwise>
		</choose>
	</template>

	<!-- given a list of 'sub_element's insert them
		where in the case of 'rng:choice' elements choosing
		the subelement based on the 'choice_numbers' given
	-->
	<template name="rng_to_dnf_helper" as="element()*">
		<param name="sub_elements" as="element()*"/>
		<param name="choice_numbers" as="xs:integer*"/>

		<choose>
			<when test="$sub_elements[1]/self::rng:choice">
				<copy-of select="$sub_elements[1]/*[$choice_numbers[1]]"/>
				<call-template name="rng_to_dnf_helper">
					<with-param name="sub_elements" select="$sub_elements[position() != 1]" as="element()*"/>
					<with-param name="choice_numbers" select="$choice_numbers[position() != 1]" as="xs:integer*"/>
				</call-template>
			</when>
			<when test="$sub_elements[1]/self::rng:optional">
					<!-- print optional content -->
				<if test="$choice_numbers[1] = 1">
					<copy-of select="$sub_elements[1]/*"/>
				</if>
				<call-template name="rng_to_dnf_helper">
					<with-param name="sub_elements" select="$sub_elements[position() != 1]" as="element()*"/>
					<with-param name="choice_numbers" select="$choice_numbers[position() != 1]" as="xs:integer*"/>
				</call-template>
			</when>
			<when test="count($sub_elements)">
				<copy-of select="$sub_elements[1]"/>
				<call-template name="rng_to_dnf_helper">
					<with-param name="sub_elements" select="$sub_elements[position() != 1]" as="element()*"/>
					<with-param name="choice_numbers" select="$choice_numbers" as="xs:integer*"/>
				</call-template>
			</when>
			<when test="count($choice_numbers)">
				<sequence select="eoa:error('rng_to_dnf', 'rng_to_dnf_helper: choice numbers left')"/>
			</when>
		</choose>

	</template>

	<!-- default rule: just copy element -->
	<template mode="rng_to_dnf" match="node() | @*">
		<copy>
			<apply-templates mode="rng_to_dnf" select="@*|node()"/>
		</copy>
	</template>

	<!-- return all indices where a sequence is non-zero, e.g.
		indices_from_bin_seq((1, 0, 1)) = (1,3)
	-->
	<function name="eoa:indices_from_bin_seq" as="xs:integer*">
		<param name="subset" as="xs:integer*"/>
		<for-each select="$subset">
			<if test=". = 1">
				<value-of select="position()"/>
			</if>
		</for-each>
	</function>

	<function name="eoa:all_seqs" as="xs:string*">
		<param name="input" as="xs:integer*"/>
		<!--
		<message>all_seqs: <value-of select="$input"/></message>
		-->
		<choose>
			<when test="count($input) = 0">
				<value-of select="()"/>
			</when>
			<otherwise>
				<for-each select="1 to $input[1]">
					<variable name="leading" as="xs:string" select="xs:string(.)"/>
					<!--
					<message>debug:<value-of select="."/></message>
					-->
					<variable name="rest" as="xs:string*" select="eoa:all_seqs($input[position() != 1])"/>
					<choose>
						<when test="count($rest) > 1">
							<for-each select="$rest">
								<value-of select="concat($leading,' ', .)"/>
							</for-each>
						</when>
						<otherwise>
							<value-of select="$leading"/>
						</otherwise>
					</choose>
				</for-each>
			</otherwise>
		</choose>
	</function>

</stylesheet>