Add tools directory with XSLT and RELAX NG.

tools/relaxng/.gitignore

+*.rnc

tools/relaxng/Makefile

+.PHONY: all clean
+
+all: yin-html.rnc
+
+%.rnc: %.rng
+	trang -I rng -O rnc $< $@
+
+clean:
+	rm -f *.rnc

tools/relaxng/yin-html.rng

+<?xml version="1.0" encoding="utf-8"?>
+
+<!-- Program name: yin-html.rng
+
+Copyright © 2013 by Ladislav Lhotka, CZ.NIC <lhotka@nic.cz>
+
+RELAX NG schema for YIN with extensions for HTML markup.
+
+NOTE:
+
+This schema extends yin.rng by adding support for the following
+non-standard YIN extension:
+
+Arguments of 'contact', 'description', 'organization' and 'reference'
+(wrapped in <text>) may contain the following HTML elements in the
+"http://www.w3.org/1999/xhtml" namespace:
+
+<html:p> - a paragraph of text
+<html:ul> - unordered list
+<html:ol> - ordered list
+
+<html:p> elements may, apart from text, also contain empty
+<html:br/> elements that cause an unconditional line break.
+
+List elements must contain one or more <html:li> elements
+representing list items with text and <html:br/> elements.
+
+A <text> element may also have the xml:id attribute and contain the
+XInclude element <xi:include>.
+
+==
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+-->
+
+<grammar xmlns="http://relaxng.org/ns/structure/1.0"
+         ns="urn:ietf:params:xml:ns:yang:yin:1"
+         xmlns:dc="http://purl.org/dc/terms"
+         xmlns:html="http://www.w3.org/1999/xhtml"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes">
+
+  <dc:title>RELAX NG Schema for YIN with HTML extensions</dc:title>
+  <dc:creator>Ladislav Lhotka</dc:creator>
+  <dc:date>2013-11-04</dc:date>
+  <dc:subject>YIN, XML syntax for YANG, HTML</dc:subject>
+  <dc:identifier>urn:ietf:params:xml:ns:yang:yin:1</dc:identifier>
+  <dc:description>
+    RELAX NG schema defines grammar for data models expressed in YIN,
+    an XML syntax equivalent to YANG, with extensions that enable HTML
+    markup in text-like contents.
+  </dc:description>
+
+  <include href="yin.rng"/>
+
+  <define name="text-content" combine="choice">
+    <optional>
+      <attribute name="xml:id">
+        <data type="ID"/>
+      </attribute>
+    </optional>
+    <oneOrMore>
+      <choice>
+        <element name="html:p">
+          <ref name="html-inline-content"/>
+        </element>
+        <element name="html:ul">
+          <ref name="html-list-content"/>
+        </element>
+        <element name="html:ol">
+          <ref name="html-list-content"/>
+        </element>
+        <element name="xi:include">
+          <attribute name="href">
+            <data type="anyURI"/>
+          </attribute>
+          <optional>
+            <attribute name="xpointer"/>
+          </optional>
+        </element>
+      </choice>
+    </oneOrMore>
+  </define>
+
+  <define name="html-inline-content">
+    <!-- This may be extended in the future -->
+    <mixed>
+      <zeroOrMore>
+        <element name="html:br">
+          <empty/>
+        </element>
+      </zeroOrMore>
+    </mixed>
+  </define>
+
+  <define name="html-list-content">
+    <oneOrMore>
+      <element name="html:li">
+        <ref name="html-inline-content"/>
+      </element>
+    </oneOrMore>
+  </define>
+
+</grammar>