order.sct

随书的代码

<?xml version="1.0"?>
<schema xmlns="http://www.ascc.net/xml/schematron">
  <title>A Schematron Schema for Orders</title>
  <pattern>
    <rule context="Order">
      <!-- Due to round-off error, floating point numbers 
           should rarely be compared for direct equality. 
           For this purpose, it's enough if they're accurate 
           within one penny. -->
      <assert test="(Shipping+Subtotal+Tax - Total)&lt;0.01 
                and (Shipping+Subtotal+Tax - Total)&gt;-0.01">
        The subtotal, tax, and shipping 
        must add up to the total.
      </assert>
      
      <assert test= 
       "(Subtotal+Shipping)*((Tax/@rate) div 100.0) 
         - Tax &lt; 0.01 and (Subtotal+Shipping)*((Tax/@rate) 
         div 100.0)-Tax &gt; -0.01
      ">
        The tax was incorrectly calculated.
      </assert>
  
    </rule>
  </pattern>
</schema>