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Joel on Software

Alternatives to VSA

Does anyone know of any alternatives to Microsofts VSA for allowing scripting in .Net applications?

I know the .Net class library includes support for loading scripts at runtime, but I'm particularly interested in having an IDE to create these scripts that could be shipped with the application.

Samuel Jack
Monday, March 03, 2003

Hello, I'm Aaron Boodman. I work in NYC at Riskclick doing .Net dev. Among other things, my company recently had me look at VSA as a method to allow users to script our workflow app.

Personally, the alternatives I found were:

- use old school activeX scripting languages. Many downsides here: lots of type translation between script types, com, and .net; performance should be significantly worse than vsa; support may be a thing of the past with vsa coming up.
- use xslt with xml. this one's kinda weird, and may be specific to our situation, but we were able to substitute a scripting language with xslt and xpath. Although alot more rigorous, it did give us a self-documenting interface to the types users create.

It looks like we'll be going with the xml route, although I am personally still fighting for vsa. Out of curiosity, what problems do you see with it? Looked like alot of fun to me...

Aaron Boodman
Monday, March 03, 2003

Just to clarify: I'm looking for alternatives to the VSA IDE, not the VSA runtime. On the whole I think the VSA runtime technology looks pretty good.

The main problem with the IDE is the pricing: $10,000 for an SDK licence, and $109 for every copy of the IDE shipped with an application.

There is one slight technical issue, as far as I remember: if a script is loaded into the current AppDomain, it has to remain in memory until the AppDomain is unloaded. So unless you don't mind old scripts accumulating in memory, you have to create a new AppDomain, and unload the old one, every time a user modifies a script.

Samuel D. Jack
Monday, March 03, 2003

Since making my earlier enquiries I have discovered SharpDevelop:

http://www.icsharpcode.net/OpenSource/SD/Default.aspx

While it might not be entirely suitable as a VSA replacement ATM, it certainly looks as if it is heading that way. At the very least, it would help users to develop plug-ins for an app without having to splash out for Visual Studio

Samuel D. Jack
Wednesday, March 12, 2003

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