Now that you have the VMD file that generates the XML text, the next step is to create a VMD file to generate the HL7 version 3 message. This step is not that complicated, as this VMD file calls an external Python module to perform the conversion. (This module is described in Loading the Python Module Into Iguana.)

To create this VMD file:

• In Chameleon, in the Toolbar, click New to create a new VMD file.
• From the Workspace menu, select Import Segments From Library.
• In the Import Segments From Library window, select the Import segments from a library radio button, and select HL7 2.6 from the list box. Click Next.
• In the list of segments, select MSH. Click Next and Finish to import the MSH segment into your VMD file.
• In the Toolbar, click Message. This creates a new message, named Message1, in the Workspace.
• In the Workspace, in the Message1 definition, double-click Message Grammar. The Message Grammar window appears.
• If it is not already there, drag the MSH segment from the Workspace to the Segment Grammar panel of the Message Grammar window.
• In the Toolbar, click Options. In the Options window, click the Special Messages tab.
• From the Default (unidentified message) list box, select Message1. This ensures that all incoming messages are processed by this message definition. Click OK to close the Options window.
• From the Chameleon menu, select Global Inbound Script. In the window that appears, type or copy the following Python script:

value = 'MSH' + value

This code is required because Chameleon expects all messages to start with an MSH segment, whereas the messages this VMD file will be receiving have been converted to XML data by the other VMD file.

• In the Workspace, in the Message1 definition, double-click Transformation Script.
• In the window that appears, type or copy the following script:

import hl7version3

value = hl7version3.hl7version3(value[3:])

This code calls the hl7version3() Python function, which does the actual conversion work. It is passed value[3:] as an argument because the Global Inbound Script added MSH to the value variable. value[3:] removes the first three characters - the MSH characters - from value before passing it to hl7version3().

• In the Toolbar, select Transform. In the Transformation window, select the Scripted Transformation radio button.
• Save this VMD file.

	For a copy of this VMD file, click this link: v3generate.vmd.