Specific Details

Read bytecode annotations and debug data from currently running code.

This would effectively extend the debugger's "vocabulary" from PIR to all Parrot-supported HLL's.

Add an interface for code instrumentation and introspection.

This would not take very long as I may just borrow the code already present in parrot-instrument.

Create an extension that would open an interpreter and be able to run code within it one opcode at a time.

Implement a shell as a user interface. Will be able to able to interpret commands, display information about current location, etc.

This may as simple as an NQP eval loop with a global dispatch table for user commands.

Use the FileHandle PMC to make the command shell a little more friendly. We can also add command line editing, command history, and tab completion.

A basic command set would include things like:

Start and continue execution with the ability to add arguments if they're not specified on the command line.

Creating breakpoints at a specific line or function.

Watch Parrot registers (including PMC's).

Stepping through code either forward or backward. Execute either a single PIR opcode or all opcodes until the next annotation line change.

Changing the current working directory of the program.

Backtrace using the CallContext and Exception PMC.

Bytecode disassembly (possibly with pbc_dump).

Scripting. For instance, interpreting a file as a set of debugger commands.

There's much, much more that can be added in the future. These are just a few.

Trace all open file handles.

This would also mean it'd have to trace all child processes.

Dynamic memory analysis.

Check arguments to function calls for uninitialized or invalid values.

Place a watch on all or individual PMC's to detect when it has been reclaimed by the garbage collector.

Timeline:

* To avoid redundancy, referring to "design" here will imply code design, unit test design, and documentation design. *

At the beginning of each week, there will be a discussion with the mentor(s) to make a weekly outline and a set of goals describing what needs to be accomplished each week.

Begin designing initial set of commands. A good starting point would be: enable/disable breakpoints, start/continue execution, stepping, print registers, source listing, help, etc

commands for bytecode disassembly, command scripting, printing information about the interpreter, etc.