Rolling your own scripting engine vs integrating Microsoft VSTA

Here are some reasons why you should consider integrating VSTA rather than writing your own scripting solution: 

In VSTA, version 1, application customization is focused on Add-in assemblies (not scripts) because Microsoft required security, process isolation and versioning to be a fundamental part of application extensibility going forward.  Microsoft's foresight in this matter is a great advantage to you, the ISV, as you release your application and grow a scripting community around it, though it adds some complexity to the initial integration process.  In the future, VSTA may provide ways to make it easier to create macros/scripts rather than add-ins.

 VSTA is already running on the client and server in MS Office System's InfoPath 2007 and spec’d for MS SQL Server Integration Services, so it’s clearly ready for your application. 

A truly great thing about integrating VSTA is that it will continually inherit innovations from the VSTA development team, Visual Studio Tools for Office (VSTO), the .NET framework and Visual Studio as well.

VSTA Design time and run time bits are all based on the .Net framework allowing you to use productivity features like code help, intellisense, etc. in your integration process.

The VSTA IDE is lighter weight build of Visual Studio (same bits) with productivity features like code help, intellisense, etc. that you can offer your users.

Valuable VSTA macros, recorded or written in an organization, can be opened in Visual Studio Professional, so that any developer on the IT staff can modify and maintain them.

Building your own plug-in system is more complex than you may think when you consider security, process isolation and versioning in your design (which you should).  When you design-in VSTA, you will enjoy the architectural contributions (like MAF) of thousands of developers in the extensibility community, Microsoft’s regular improvements to VSTA, and Summit Software’s guidance through the entire integration process.

Summit regularly adds new documents and samples that more fully explore the details of integrating VSTA.  We post these samples on our site.