Sunday, October 7, 2012

How to reference and reuse LinqPad queries

One missing feature from LinqPad is the ability to easily reuse code in a query we wrote in other queries.

If we really want to do it we have the following options:
  • Copy and paste the code into the new query
  • Open Visual Studio, create a project, create a class and copy the code you want to reuse. Compile the project and finally reference the generated dll from your query.
  • Compile the LinqPad query directly (using a special script), then reference the generated dll from your query.

Today we will look at the third option. Found in the .Net framework is a very interesting API called the CodeDOM API. This API can be used to compile .Net code at run-time, like the compiler does. With this, we will be able to parse a LinqPad query and compile it.

This is what we will look into right now.

Compiling a LinqPad query

Those are the steps we need to do to accomplish query compilation:
  1. Read the query and extract the options, usings and references
  2. Create the CodeDOM objects and set the options and references
  3. Create a string of the code file including the usings and wrap the query code inside a class
  4. Compile the code

I'll explain in details each steps in future blog posts but for now I'll give you my query to compile LinqPad queries. You will notice that this is a self compiling query as the query compile itself to a dll I can reuse it to compile other queries!

You can figure out the Compiler class usage from the Main function for now.

Additional Namespace Imports


Query (C# Program)