<eTree>

<eTree> (嵌入樹狀結構) 提供樹元素的替換，用來表示整齊具有根節點的樹狀結構。 19.3 Another Tree Notation
組件nets — 19 Graphs, Networks, and Trees
屬性 att.typed (@type, @subtype)
value提供一個嵌入樹狀結構值，該嵌入樹狀結構為一個功能結構或其他分析元素。
狀態 可應用時必備的
資料類型 

<rng:ref name="data.pointer"/>
data.pointer
值 A valid identifier of a feature structure or other analytic element.
屬於
eTree forest triangle model.divPart
可包含
core: label ptr ref
nets: eLeaf eTree triangle
宣告

<rng:element name="eTree">
<rng:ref name="att.global.attributes"/>
<rng:ref name="att.typed.attributes"/>
<rng:optional>
 <rng:attribute name="value">
  <rng:ref name="data.pointer"/>
 </rng:attribute>
</rng:optional>
<rng:group>
 <rng:optional>
  <rng:ref name="label"/>
 </rng:optional>
 <rng:zeroOrMore>
  <rng:choice>
   <rng:ref name="eTree"/>
   <rng:ref name="triangle"/>
   <rng:ref name="eLeaf"/>
   <rng:ref name="model.ptrLike"/>
  </rng:choice>
 </rng:zeroOrMore>
</rng:group>
</rng:element>
element eTree
{
   att.global.attributes,
   att.typed.attributes,
   attribute value { data.pointer }?,
   ( label?, ( eTree | triangle | eLeaf | model.ptrLike )* )
}
例子
<eTree n="ex1">
 <label>PP</label>
 <eTree>
  <label>P</label>
  <eLeaf>
   <label>with</label>
  </eLeaf>
 </eTree>
 <eTree>
  <label>NP</label>
  <eTree>
   <label>Art</label>
   <eLeaf>
    <label>the</label>
   </eLeaf>
  </eTree>
  <eTree>
   <label>N</label>
   <eLeaf>
    <label>periscope</label>
   </eLeaf>
  </eTree>
 </eTree>
</eTree>