- Add support for setBreakpoints request
- Add source locations to stackTrace response
- Source-level stepIn/stepOut/next executions
All of these only work if debug information is available. Otherwise they
work at the instruction level as before.
This adds source-level debugging capabilities to the command-line
debugger, utilizing debug information generated by sys4dc. The debug
information format is documented at:
https://github.com/kichikuou/sys4dc/blob/master/docs/debug_info.md
The location of the debug information file can be specified with the
`--debug-info` command-line flag. If not specified, xsystem4 will
attempt to load it from `gamedir_path("src/debug_info.json")`.
When debug information is available, a breakpoint can be set at a
specific line in a file using `breakpoint <file> <line>`. Also, `step`
and `next` commands advance execution to the next source line (this is
naively implemented by repeating instruction-level stepping).