• Chapter 1: Getting Started with Stylus Studio
• Chapter 2: Editing and Querying XML
• Chapter 3: Converting Non-XML Files to XML
• Chapter 4: Working with XSLT
• Chapter 5: Creating XSLT Using the XSLT Mapper
• Chapter 6: Debugging Stylesheets
• Chapter 7: Defining XML Schemas
• Chapter 8: Defining Document Type Definitions
• Chapter 9: Writing XPath Expressions
• Chapter 10: Working with XQuery in Stylus Studio
  • Getting Started with XQuery in Stylus Studio
  • Building an XQuery Using the Mapper
  • Debugging XQuery Documents
  • Creating an XQuery Scenario
• Chapter 11: Composing Web Service Calls
• Chapter 12: Accessing Relational Data as XML
• Chapter 13: Extending Stylus Studio
• Chapter 14: Stylus Studio Reference

Home > Online Product Documentation > Table of Contents > Function Blocks

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:

If a standard function does not provide the functionality you need, create a user-defined function. See User-Defined 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.

See User-Defined Functions to learn more about creating user-defined functions in Stylus Studio.

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 249. Function Block

Input ports

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

Flow ports, on the top of function blocks, are the same for FLWOR, function, and IF blocks. See 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 define your own functions in XQuery, such as the following:

              define function total-price( $i as element) as xs:decimal
               

              {
               

                let $subtotals := for $s in $i return $s/quantity * $s/USPrice
               

                return sum( $subtotals )
               

              }
               

            

This particular user-defined function, which takes an element as its argument and returns a sum of the prices, might be used as follows (shown in italics):

              <Catalog>
               

              	{
               

              		for $book in /books/book
               

              		return
               

              		<Book>
               
			<Price>
               

              				{total-price($book/@bookid)}
               
			</Price>
               

              		</Book>
               

              	}
               

              </Catalog>
               

            

When you create a user-defined function, Stylus Studio adds it to the New > User Functions shortcut menu available when you right-click the mapper canvas.

Figure 250. User-Defined Functions

This makes it easy to reuse a user-defined function on the Mapper tab once it has been defined in the XQuery source.

concat Function Blocks

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