document backtrace functionality
ECL has two kinds of backtraces: c-backtrace and backtrace (defined in tpl.lisp). We need to examine the interface and document it. We could also review swank's implementation for ECL after that (backtraces work there, but they lack some features).
also there seems to be a bug in backtrace
:
> (break)
Condition of type: SIMPLE-CONDITION
Break
Available restarts:
1. (CONTINUE) Return from BREAK.
2. (RESTART-TOPLEVEL) Go back to Top-Level REPL.
Broken at SI:BYTECODES. [Evaluation of: (BREAK)] In: #<process TOP-LEVEL>.
>> :bds
FRS[4]: ---> IHS[1],BDS[0]
BDS[1]: *DEBUGGER-HOOK* =
Debugger received error of type: SEGMENTATION-VIOLATION
Detected access to an invalid or protected memory address.
Error flushed.