I started to work in an HQL addin for Visual Studio two weeks ago. As described in the project site:

This Visual Studio addin will provide the following features for the HQL file extension:
-syntax highlighting (done),
-syntax checking (done)
-intellisense (not yet)

Currently the addin support syntax highlighting and checking as you can see in the following screenshot:

One of the more interesting part of this, is that I have not implemented a parser or anything. I have only used the lexer and the parser inside NHibernate 3, so these features will be up to date always. In fact you can see the error “No viable alternative” that is common for most of the ANTLR parsers.

My idea is to support Intellisense as well, so I have reached Felice Pollano. He already has done a lot of work for other application named NHWorkBench and we are willing to cooperate for the intellisense part.

There is a step by step guid on how to use “hql” files with nhibernate here.

I have published an alpha release in the Visual Studio Online Gallery, so is very easy to install it:

If you are doing HQL have a look to my pluggin and let me know your comments!