To provide debugger support for your language, you need to either implement your own debug engine or target the Common Language Runtime (CLR), which includes a default debugger for Microsoft intermediate language (MSIL) code. If you target the CLR, the Locals, Watch and Autos debugging windows do not work. These windows are enabled when you supply an expression evaluator (which is represented by an IDebugExpressionEvaluator interface) for your language. Given this, the Autos window normally fails to show relevant expressions; however, the IBabelService Interface can automatically provide Autos window expressions to the debugger if you are using the default IBabelService implementation and your parser calls the autoExpression method in the StdService class for each expression that should appear in the Autos window. See How-to: Enable Debugger Autos Window Support for more details.
You do not need to create an expression evaluator to use the common language runtime's debug engine if, for example, you only want to support step debugging. For more information on creating an expression evaluator, see Writing a Common Language Runtime Expression Evaluator in the Visual Studio Debugging SDK.
See Also
Concepts
Using the Default Babel Implementation