Hi Danny,

It depends what your trying to achieve. Roughtly speaking the codeDOM and fsi do the same thing, take some code as text and compile it to a dll and then load and execute this. I think they use slightly different techniques to achieve this, the codeDOM invokes the command line compiler, while fsi creates the dll directly in memory (I think), but this is unimportant - an implementation detail. What fsi does that's different is keep a dictionary of top level identifiers and their values and ensure that they are available to future code snippets. It would be quite difficult to do a hand rolled version of this using codeDOM.

However quite often when inculding scripting in your application it's not that important for people to be able interact with there old code definitions, more often than not you they just want to run scripts against objects/modules that exist in the application. It's pretty staight forward to use codeDOM to achieve this, I have an created an ant colony simulation that uses this apporach:

[link:code.google.com]

Cheers,
Rob