Attribute</span></dt>
<dd><p>
                  This is the type of the token value (attribute) supported by token
                  instances representing this token type. This attribute type is
                  exposed to the <span class="emphasis"><em>Spirit.Qi</em></span> library, whenever
                  this token definition is used as a parser component. The default
                  attribute type is <code class="computeroutput"><span class="identifier">unused_type</span></code>,
                