Microsoft is shipping T4, an ASP-like template engine. It's included in the 'Guidance Automation Extensions' and with the DSL tools package now part of the Visual Studio SDK, so it's free.
Actually, it looks it maybe redistributable, and in that case, as far as I know, will be the first template engine that can be freely redistributable. The 'maybe' is because the EULA is not very clear. I hope it will be more specific in future releases.
My fellow Visual Studio Wizard wrote a T4 editor for VS 2005 that includes several cool features. If you are working with the GAT/GAX, with DSLs or using T4 for generating code in other context, you should be using it.
After reading Victor's article about Virtual Path Providers I thought it was a very cool technology and that it was possible to do very interesting things with it.
One of the things I wanted to try was to be able to kind of override a single file in an asp.net application in a specific installation of the web app.
If you are using a code generation tool for the ASP.NET presentation layer, it's very possible that you will want to radically change some of the generated files, and leave the rest as they are. There are several solutions to this problem, but using a VPP looks like a very good one. Instead of modifying the file and finding a way to tell the code-generator to not to overwrite it, you can create a folder called 'Branchs', and put the modified file there. You can put just the .aspx/.ascx, or also the .cs, or the .css, or whatever you want.
The other scenario that is more appealing to people that does not use code generation for their ASP.NET layer, is application customization. Suppose you want to install a single application for several customers, and each customer requires minor tweaks in the UI. You can build complex plumbing to support that, and based on metadata customize the pages in runtime, or you can just put the modified files in a 'Customer1' folder, and make the VPP return those ones. Of course, it's not the best from a maintenance point of view. If you need to make a change in a page for two customers, you'll need to do it twice, but this problem is not easy to solve anyway, so I'm not sure how bad it is.
You could also have a hierarchy, like a folder for each country with country-specific customizations, and below that one, the customer specific ones. The VPP will first look in the customer specific ones, then in the country-specific ones and then in the main web directory.
Russ Garner, one of my favorite DeKlarit users actually built it. Check it here.
Today was the last day of the SC-BAT Workshop in Building 20.
The PAG team basically showed the stuff they are building using the CAB and GAT.
We've been using the CAB for a while and it rocks. It's not simple to grasp but once you got the basic concepts it's very powerful. It helps you to get used to ObjectBuilder which is probably going to be part of most of the new applications we write.
The GAX is also a cool piece of work, and it's a great tool to package guidance. I can think of a lot of cool uses for it... If I just could clone myself..
It was fun to hang around with the SouthWorks, the Clarius and the Infragistics guys.
Now the pictures... Below you can find the dream team, Oscar Calvo, Brad Wilson, Sam Gentile, Steve Eichert and Wojtek Kozaczynski
Here there is a view of the fully packed lab room:
And we'll finish with Daniel Cazzulino and Leandro Olivestro in the kitchen after eating all the (free as in beer) Haagen Dazs
