Eli Zaretskii writes: > Daniel said lldb supports the MI protocol. If that is true, lldb is > already supported. Can someone try that and see if that works, and if > not, tell why? > > Thanks. The tool `lldb-mi` is not installed on macOS by default (on 10.11 El Capitan that is). But it can be installed with Homebrew. brew install llvm --with-lldb --with-clang But that is outside the question. I tried to use it: M-x gud-gdb /usr/local/opt/llvm/bin/lldb-mi hello and when setting a breakpoint I got the following error: error: command 'breakpoint' did not recognize 'hello .swift:28' as valid (subcommand might be invalid). ambiguous command 'break'. Possible completions: breakpoint So, no, it is not working at the moment. Regards, Toon