Execute a command using selected text

[sminez]

Implements #31

@davcam I wont ask you for a review of what's going on here as that's a bit much given I'm the only one familiar with the internals of the project(!) but this PR branch should be buildable locally for you to try this out while I work on adding test coverage of the new mouse behaviour. (@srenatus you've seemed quite keen on seeing more acme functionality in ad so you might be interested in this as well!)

Summary of changes

• Mouse interactions have been overhauled to support dragging right and middle clicks to load and execute text respectively and Acme style chording:
  • Left (click+release): set Cur Dot at the location of the click
  • Left (click+hold+release): set Range Dot from click->release with click active
  • Right (click+release): Load Dot (expanding current dot from Cur if needed)
  • Right (click+hold+release): Load click->release
  • Middle (click+release): Execute Dot (expanding current dot from Cur if needed)
  • Middle (click+hold+release): Execute click->release
  • For Execute actions, if the current Dot is a Range then it is used as an argument to the command being executed
  • Hold Left + click Right: Paste into selection
  • Hold Left + click Middle: Delete selection (cut)
  • Hold Right + click either: cancel Load
  • Hold Middle + click either: cancel Execute
• Fsys execute events may now be preceded by a "chorded argument" event ('A' as the type in the event file) denoting the location of the chorded argument
• Fsys event text is truncated at the first newline character or at 256 characters (whichever comes first)
• There are two new config color properties: load-bg-color and exec-bg-color which are used to control the highlight color of right and middle button drag selections respectively

Demo

https://github.com/user-attachments/assets/35d25a1b-2271-4b4d-b4bf-4f881a4e6a22

[srenatus]

I've watched the demo, it's very nice. I'm especially a fan of Acme's cut/paste chords.

One thing I've noticed, and that's unrelated to this PR (sorry) and probably impossible (double-sorry for bringing it up regardless): In acme, if you right-click to search something, the cursor jumps to the findings. So to keep searching, you can keep pressing right-click, right-click, right-click. It's no big deal, I think in ad you'd just keep pressing enter -- the selection moves, after all, just the mouse pointer cannot.

Another peanut gallery remark, it would be pretty useful if the screenshare would show what you pressed while recording the demo. It's more or less clear for this demo, but I'd like to learn more about other people's general usage of key bindings etc when using the editor. (Anecdotally, it took me a while to find <space> b after I saw that something like this must exist in a screencast. Similarly, figuring out that - is a thing if fd is installed (or the find-command configured differently) changed my experience a lot.)

[srenatus]

Also: thanks for pushing this forward. 🥳

[sminez]

Thanks for taking a look @srenatus! The warping of the cursor is something I'd love to get working but I'm reasonably sure it'd be a massive hack (if possible at all) in a terminal UI. So at some point I really should look at writing a full GUI.

The new ":help" command shows how some things work but I need to find time to finish the documentation and ideally generate it from the source code.

As for showing interactions in the demos, I was wondering about that and I can probably actually build that in to ad itself, echoing the inputs out in the status line. One to look at later 😅