7. One or more device-readable computer storage media with device-executable instructions for performing steps comprising: reading a line of source code; parsing the line of source code for a command; calling into a debug hook, wherein the debug hook is a respective one of a plurality of Intermediate Language (IL) islands that maps to the line of source code, the respective one of the plurality of IL islands being callable by an interpreter to enable a debugger to debug the line of source code mapped to the respective one of the plurality of IL islands; and executing the command corresponding to the parsed line of source code; said calling into the debug hook comprises calling the respective one of the plurality of IL islands and passing a function pointer, the function pointer pointing to a function in the source code, and calling the function pointed to by the function pointer and executing the function.
7. One or more device-readable computer storage media with device-executable instructions for performing steps comprising: reading a line of source code; parsing the line of source code for a command; calling into a debug hook, wherein the debug hook is a respective one of a plurality of Intermediate Language (IL) islands that maps to the line of source code, the respective one of the plurality of IL islands being callable by an interpreter to enable a debugger to debug the line of source code mapped to the respective one of the plurality of IL islands; and executing the command corresponding to the parsed line of source code; said calling into the debug hook comprises calling the respective one of the plurality of IL islands and passing a function pointer, the function pointer pointing to a function in the source code, and calling the function pointed to by the function pointer and executing the function. 9. The one or more device-readable computer storage media of claim 7 , wherein the steps further comprise stepping over from the respective one of the plurality of IL islands to another one of the plurality of IL islands.