stm:basis

The stm:basis operation generates the basis set for the given xpath. In linear algebra the basis is the set of unique values from which all others can be composed. stm:basis computes the unique document for a given xpath. Sounds complex but it's not so bad and is very useful. Say you want to know the set of unique values of, for example, @type attribute in a document. Use stm:basis with xpath="//@type". It's then easy to transform that result into say an XHTML form select element. What if you wanted to know the set of unique instructions used in an idoc? Use xpath="/descendant::type/text()". Or the set of unique customers from a list of multiple orders - use something like xpath="/orders/order/customer/name/text()" With declarative processing of XML it is very useful to be able to examine the fundamental structure of a document without the noise of the data. Using xpath="//*" returns the skeleton document without it's data. stm:basis works with any xpath location these can be elements, text or attributes or any combination.

Example

Example1: The basis elements This example creates the basis document from which the source document was a linear combination. Checkout data.xml to see how it is composed of this basis set. <idoc>   <seq>     <instr>       <type>stm</type>       <operand>data.xml</operand>       <operator>         <stm:group xmlns:stm="http://1060.org/stm">           <stm:basis xpath="//*" />         </stm:group>       </operator>       <target>this:response</target>     </instr>   </seq> </idoc> Try it

Example 2: The unique attribute values This example returns the set of all attributes and their unique values. They remain in the context of the document tree structure. <idoc>   <seq>     <instr>       <type>stm</type>       <operand>doc.xml</operand>       <operator>         <stm:group xmlns:stm="http://1060.org/stm">           <stm:basis xpath="//*/@*" />         </stm:group>       </operator>       <target>this:response</target>     </instr>   </seq> </idoc> Try it