Hi
while working with some nasal "core files" I had a need of selective backtraces to understand the code flow, e.g. when and where a function is called. This lead to an extension of the debug.nas, namely a class Breakpoint
It is maybe not exactly a breakpoint as in an interactive debugger but it allows to selectively dump some state information w/out killing the script.
Documentation: http://wiki.flightgear.org/Nasal_library/debug
Code should be merged soon to fgdata (next)