1. At a computer system including a processor and system memory, a computer-implemented method for providing debugging functionality for debugging a domain specific language within an interactive development environment, the method comprising: an act of displaying an interactive development environment including a domain specific language (DSL) grammar input receiving area that allows the user to view and interact with DSL grammar inputs, a DSL language input receiving area that allows the user to view and interact with DSL language inputs and a parse output area that allows the user to view the current state of the DSL parser; an act of receiving a step input from the user indicating that the interactive development environment is to begin stepping through each DSL language input to determine whether the DSL language inputs have created an error relative to the DSL grammar that defines acceptable DSL language inputs; and an act of presenting the resulting output for each DSL language input, such that as the user provides subsequent step inputs, the interactive development environment successively steps through each DSL language input and presents, at each step, the DSL grammar inputs, the DSL language inputs and the corresponding output in the parse output area.