Constructing the Mashup Result, Inputs or Intermediate Variables
You define the structure of the result that is returned from a mashup operation in these statements:
<select> (within <mashup>, <operation> or <macro>)
<select> within a
<join> command to select specific items within a set of repeating items.
<group> constructs repeating structures from sorted and optionally filtered node sets.
You can also use these statements to construct complex input parameters or any complex intermediate variable. You can construct the contents of variables (in <variable>) or input parameters (in <input>) using literal XML.