<xsd:schema
  xmlns:xsd="http://www.w3.org/2001/XMLSchema"
  xmlns:bgf="http://planet-sl.org/bgf"
  xmlns:xbgf="http://planet-sl.org/xbgf"
  xmlns:ldf="http://planet-sl.org/ldf"
  xmlns:xldf="http://planet-sl.org/xldf"
  targetNamespace="http://planet-sl.org/xldf">

  <xsd:annotation>
    <xsd:documentation>
      LDF transformations
    </xsd:documentation>
  </xsd:annotation>

  <xsd:import namespace="http://planet-sl.org/ldf" schemaLocation="ldf.xsd"/>
  <xsd:import namespace="http://planet-sl.org/bgf" schemaLocation="bgf.xsd"/>
  <xsd:import namespace="http://planet-sl.org/xbgf" schemaLocation="xbgf.xsd"/>

  <xsd:element name="sequence">
    <xsd:annotation>
      <xsd:documentation>
        Sequential composition of multiple transformations.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:complexType>
      <xsd:group ref="xldf:transformation" minOccurs="0" maxOccurs="unbounded"/>
    </xsd:complexType>
  </xsd:element>

  <xsd:group name="transformation">
    <xsd:annotation>
      <xsd:documentation>
        Here is a grouped list of all the XLDF transformations.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:choice>
      <xsd:element ref="xldf:insert"/>
      <xsd:element ref="xldf:import"/>
      <xsd:element ref="xldf:move"/>
      <xsd:element ref="xldf:rename"/>
      <xsd:element ref="xldf:append"/>
      <xsd:element ref="xldf:add-section"/>
    </xsd:choice>
  </xsd:group>

  <xsd:element name="insert">
    <xsd:annotation>
      <xsd:documentation>
        TBD
      </xsd:documentation>
    </xsd:annotation>
    <xsd:complexType>
      <xsd:sequence>
       <xsd:choice>
         <xsd:element name="before">
           <xsd:complexType>
             <xsd:group ref="ldf:insideSimpleText"/>
           </xsd:complexType>
         </xsd:element>
         <xsd:element name="after">
           <xsd:complexType>
             <xsd:group ref="ldf:insideSimpleText"/>
           </xsd:complexType>
         </xsd:element>
       </xsd:choice>
       <xsd:element name="content" type="ldf:SimpleText"/>
      </xsd:sequence>
    </xsd:complexType>
  </xsd:element>

  <xsd:element name="add-section">
    <xsd:annotation>
      <xsd:documentation>
        TBD
      </xsd:documentation>
    </xsd:annotation>
    <xsd:complexType>
      <xsd:choice>
        <xsd:group ref="ldf:front-simple-section"/>
        <xsd:group ref="ldf:front-list"/>
        <xsd:group ref="ldf:lexical"/>
        <xsd:element name="core" type="ldf:StructuredSection"/>
      </xsd:choice>
    </xsd:complexType>
  </xsd:element>

  <xsd:element name="move">
    <xsd:annotation>
      <xsd:documentation>
        TBD
      </xsd:documentation>
    </xsd:annotation>
    <xsd:complexType>
      <xsd:sequence>
        <xsd:element name="section" type="xsd:string"/>         <!-- IDREF -->
        <xsd:element name="inside" type="xsd:string"/>         	<!-- IDREF -->
      </xsd:sequence>
    </xsd:complexType>
  </xsd:element>

  <xsd:element name="rename">
    <xsd:annotation>
      <xsd:documentation>
        TBD
      </xsd:documentation>
    </xsd:annotation>
    <xsd:complexType>
      <xsd:sequence>
        <xsd:element name="from">
          <xsd:complexType>
            <xsd:choice>
              <xsd:element name="id" type="xsd:string"/>
              <xsd:element name="title" type="xsd:string"/>
            </xsd:choice>
          </xsd:complexType>
        </xsd:element>
        <xsd:element name="to" type="xsd:string"/>
      </xsd:sequence>
    </xsd:complexType>
  </xsd:element>

  <xsd:element name="append">
    <xsd:annotation>
      <xsd:documentation>
        TBD
      </xsd:documentation>
    </xsd:annotation>
    <xsd:complexType>
      <xsd:sequence>
       <xsd:element name="where" type="xsd:string"/>			<!-- IDREF -->
       <xsd:element name="content" type="ldf:SimpleText"/>
      </xsd:sequence>
    </xsd:complexType>
  </xsd:element>

  <xsd:element name="import">
    <xsd:annotation>
      <xsd:documentation>
        Deprecated
      </xsd:documentation>
    </xsd:annotation>
    <xsd:complexType>
      <xsd:sequence>
        <xsd:element name="target" type="xsd:string"/> <!-- IDREF -->
        <xsd:element name="file" type="xsd:string"/> <!-- IDREF -->
      </xsd:sequence>
    </xsd:complexType>
  </xsd:element>
  
  <xsd:element name="transform-grammar">
    <xsd:annotation>
      <xsd:documentation>
        Deprecated
      </xsd:documentation>
    </xsd:annotation>
    <xsd:complexType>
      <xsd:group ref="xbgf:transformation"/>
    </xsd:complexType>
  </xsd:element>

  <xsd:group name="scope">
    <xsd:annotation>
      <xsd:documentation>
        Several transformation operators are possibly restricted to
        a specific scope as opposed to their application to the full
        input grammar. Two major forms of scope can be identified.
        First, a production can be appointed by its label. Second, a
        definition (nonterminal) can be appointed by its defined
        nonterminal. Arguably, one may want to be able to appoint a
        production even when it is not labeled, but a prior designate
        transformation can then be used in order to attach a label
        to the production in question.
      </xsd:documentation>
    </xsd:annotation>
    <xsd:choice>
      <xsd:element name="label" type="bgf:label"/>
      <xsd:element name="nonterminal" type="bgf:nonterminal"/>
    </xsd:choice>
  </xsd:group>

</xsd:schema>