DAP Tools

This is a collection of tools for use with a Debugger capable of speaking the Debug Adapter Protocol aka DAP.

dap-tui

You have that debugger running. Breakpoints set. But.... what are the values on the stack right now?? How could you possibly learn that? Well, this will do it.

dap-tui connects to a DAP session and shows the values of the variables while the debugger steps through the code. You can also step right here too.

Now, maximum effect you need a multiplexer for the DAP. Without one you can drive the session but not see the code. I don't know about you but that does not sound like fun. dap-mux is one choice. dap-mux-rs is another. The Rust form has the advantage of talking either TCP or stdio.

dap-tui is an observer and only ever joins an existing multiplexer session. It does not spawn the adapter or manage the session.

# terminal 1 — adapter + mux
python -m debugpy.adapter --host 127.0.0.1 --port 5678
dap-mux --attach 5678 -p 5679

# terminal 2 — Helix drives the session
hx sieve.py    # set a breakpoint, then :debug-remote 127.0.0.1:5679 launch

# terminal 3 — the observer (this crate)
dap-tui                # connects to 127.0.0.1:5679 by default
dap-tui 5680           # custom port
dap-tui host:port      # custom host + port

Step in the editor. The TUI refreshes its variable tree whenever execution stops at a breakpoint.

Watches

Deeply-nested variables get lost when the tree re-roots on every step. Press w on a variable to pin it as a watch: it appears in a ── watched ── section pinned to the top of the list and is re-evaluated against the current frame on every stop, so you don't have to re-navigate to it. Press w again on the variable (or on its watched row) to unpin it. A watch that falls out of scope stays pinned and shows (unavailable) until it resolves again.

Keys

key	action
j / k (or ↓/↑)	move selection
l / h (or →/←)	expand / collapse the selected node (fetches children lazily on expand)
K / J	up or down a frame
Enter / Space	toggle expand/collapse
i	interactive mode. Evaluate expressions.
p	pause
c	continue
n	next
s	step into
o	step over
w	pin / unpin the selected variable as a watch
g / G	jump to top / bottom
q / Esc	quit (clean disconnect, terminal restored)

dap-script

A DSL (Domain Specific Language) exposing the Debug Adapter Protocol to scripting. Repeatable bug explorations without learning gdb or lldb scripting. It works the same for anything that speaks DAP. More in its own README.