Function Blocks

Stylus Studio supports standard functions defined by the W3C and any user-defined functions you might have created. This section describes how to work with function blocks in Stylus Studio and covers the following topics:

Standard Function Block Types

Stylus Studio provides graphic support for the following types of XQuery functions:

Creating a Function Block

The procedure for creating standard and user-defined function blocks varies slightly:

To create a standard function block:

To create a user-defined function block:

Any user-defined functions defined in the XQuery source are displayed in a sublist.

Parts of a Function Block

Function blocks are drawn as a purple block with an italic "f" at its center, and connectors, called ports, placed along the block's border. Input ports (none or more based on the function), the Flow port at the top, and the Return port on the right:

Figure 341. Function Block

Input ports are on the left side of the function block. The number and definition of input ports varies from function to function. To specify a value for an input port, drag a source document element or attribute to the port and release it.

Flow port

Return port

The Return port is on the right side of the function block. You use the Return port to map the function result directly to a target structure element or attribute, or to a FLWOR, IF, condition, or another function block.

User-Defined Functions

You can declare your own functions in XQuery, such as the following:

declare function total-price( $i as element) as xs:decimal 
{ 
  let $subtotals := for $s in $i return $s/quantity * $s/USPrice 
  return sum( $subtotals ) 
} 

concat Function Blocks

There are three types of concatenation (concat) functions for strings:

Note that only the first two input ports are associated with variables ($op1 as string? and $op2 as string?). When you map a value to the third input port (...), Stylus Studio automatically adds a fourth input port to allow you concatenate a fourth value. This behavior is repeated for each additional string you define.