Interests in a breakpoint hook/breakpoint op patch?

[Thomas Jericke <tjericke@...>]

For our project I have modified the Lua interpreter to support a new 
hook type (breakpoint hook) which is called every time the interpreter 
hits a breakpoint op.
I could turn my modifications into a patch but I still need some work to 
do to have a general solution. My current solution is very adapted to my 
own needs. And as it is, the implementation should be improved as well.
Basically I added another type of hooks that can be used with 
lua_sethook. Additionally I added a function to add a breakpoint at a 
source and linenumber. This function searches for the proto of the 
according source code and linenumber and then replaces the op_code at 
the first bytecode to op_breakpoint. Once the pc runs to such a 
op_breakpoint the hook is called (if it is installed) after the hook 
returns, the original op is executed.
The reason for this patch is performance only. We tried the current Lua 
debuggers which use the line hook and it wasn't performing fast enough 
to use it with our system. With the breakpoint hook the impact on the 
runtime is close to zero as long as you don't hit a breakpoint. There is 
a quite big overhead when you install a breakpoint but this is not such 
a big problem as usually the user doesn't change his breakpoints all the 
time.
Now as I said, I would need to do some work before I can release such a 
patch, so I would only do that if someone is actually interested in 
using it.

--
Thomas