<?xml version="1.0"?>
<grammar
    xmlns="http://relaxng.org/ns/structure/1.0"
    xmlns:if="http://projectmallard.org/if/1.0/">

<!--
This schema cannot be used on its own. It is designed to be combined
with the core Mallard schema using the version attribute.
-->

<define name="if_attr_test">
  <attribute name="test">
    <text/>
  </attribute>
</define>

<define name="if_attr_if_test">
  <attribute name="if:test">
    <text/>
  </attribute>
</define>

<define name="mal_block_attr" combine="interleave">
  <optional>
    <ref name="if_attr_if_test"/>
  </optional>
</define>

<define name="mal_block_list_item_attr" combine="interleave">
  <optional>
    <ref name="if_attr_if_test"/>
  </optional>
</define>

<define name="mal_block_steps_item_attr" combine="interleave">
  <optional>
    <ref name="if_attr_if_test"/>
  </optional>
</define>

<define name="mal_block_terms_item_attr" combine="interleave">
  <optional>
    <ref name="if_attr_if_test"/>
  </optional>
</define>

<define name="mal_block_tree_item_attr" combine="interleave">
  <optional>
    <ref name="if_attr_if_test"/>
  </optional>
</define>

<define name="if_if">
  <element name="if:if">
    <ref name="if_if_attr"/>
    <zeroOrMore>
      <ref name="mal_block"/>
    </zeroOrMore>
  </element>
</define>

<define name="if_if_attr">
  <group>
    <ref name="if_attr_test"/>
    <optional>
      <attribute name="style">
        <data type="NMTOKENS" datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes"/>
      </attribute>
    </optional>
    <zeroOrMore>
      <ref name="mal_attr_external"/>
    </zeroOrMore>
  </group>
</define>

<define name="mal_block_elements" combine="choice">
  <ref name="if_if"/>
</define>

<define name="if_choose">
  <element name="if:choose">
    <ref name="if_choose_attr"/>
    <oneOrMore>
      <ref name="if_when"/>
    </oneOrMore>
    <optional>
      <choice>
        <ref name="if_else"/>
        <zeroOrMore>
          <ref name="mal_block"/>
        </zeroOrMore>
      </choice>
    </optional>
  </element>
</define>

<define name="if_choose_attr">
  <group>
    <optional>
      <attribute name="style">
        <data type="NMTOKENS" datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes"/>
      </attribute>
    </optional>
    <zeroOrMore>
      <ref name="mal_attr_external"/>
    </zeroOrMore>
  </group>
</define>

<define name="mal_block_elements" combine="choice">
  <ref name="if_choose"/>
</define>

<define name="if_when">
  <element name="if:when">
    <ref name="if_when_attr"/>
    <zeroOrMore>
      <ref name="mal_block"/>
    </zeroOrMore>
  </element>
</define>

<define name="if_when_attr">
  <group>
    <ref name="if_attr_test"/>
    <optional>
      <attribute name="style">
        <data type="NMTOKENS" datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes"/>
      </attribute>
    </optional>
    <zeroOrMore>
      <ref name="mal_attr_external"/>
    </zeroOrMore>
  </group>
</define>

<define name="if_else">
  <element name="if:else">
    <ref name="if_else_attr"/>
    <zeroOrMore>
      <ref name="mal_block"/>
    </zeroOrMore>
  </element>
</define>

<define name="if_else_attr">
  <group>
    <optional>
      <attribute name="style">
        <data type="NMTOKENS" datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes"/>
      </attribute>
    </optional>
    <zeroOrMore>
      <ref name="mal_attr_external"/>
    </zeroOrMore>
  </group>
</define>

</grammar>