Do any debuggers support "edit and continue?"

[Joel Koltner]

"Terry Reedy" <tjreedy at udel.edu> wrote in message 
news:mailman.119.1273690025.32709.python-list at python.org...
> CPython compiles Python code (a sequence of statements) to its private 
> bytecode (a sequence of codes and operands) and then interprets the 
> bytecode. So 'edit and continue' would have to recompile the statement and 
> patch the result into the bytecode.

I believe this is what, e.g., Visual Studio does with, e.g., C++ code -- it 
compiles the modified code and then patches the binary to call the new code as 
a subroutine or somesuch.

> Another problem is recovery of state. If an exception is raised in the 
> middle of a statememt, there would need to be a means to roll back the state 
> of objects and namespaces to what they were before execution of the 
> statement started. So the interpreter would need to act like a transactional 
> database, which is not trivial.

Yeah, I can see this being challenging.  I think it's pretty cool how some 
Python debuggers will allow you to use a shell with the context set to the 
current function or any of the calling functions higher up the call stack 
hierarchy as well.

> This would also slow normal execution, so it would have to be optional.

That'd be a small price to pay. :-)  (Visual Studio only lets you do this with 
unoptimized code...)

> If would definitely be nice. Perhaps $500,000 in funding would do the trick.

Cool, if I win the lottery and add it to the "worty causes" list! :-)

Thanks for the information,
---Joel