previously.hx

A picker for everything that has passed through a register, for the Helix⁠ editor, written in Steel Scheme.

Yanks, typed commands and / searches all land in registers, and Helix gives you no way to look back at them. This shows you the lot in one fuzzy-filtered list with a preview pane, and puts whichever one you choose back at the front of its register.

Demo

Install

Requires a plugin-enabled Helix build. With forge⁠, Steel’s package manager:

forge pkg install --git https://github.com/waddie/previously.hx

Then in ~/.config/helix/init.scm:

(require "previously.hx/previously.scm")

Capture starts at load, and :previously opens the picker.

Use

Run :previously. The list holds every yank captured since Helix started, then your : history, then your / history. Type to filter across all three. The preview pane holds the whole value, which is how a yank full of whitespace becomes readable.

Rows are y, : or / for where the value came from, then the register character, then the first line of the value, then (N) when a yank spans several cursors.

Typed text filters the value. A column takes its own filter under the %name syntax Helix’s own pickers use, so %s narrows by source, %r by register and %v by value. A literal percent is \%.

Enter stages. Alt-Enter acts immediately.

Source	Enter	Alt-Enter
Yank	rewrites its register, so p pastes it	pastes it now
:	pulls it to the front of :, opens the prompt	same as Enter
/	pulls it to the front of /, so n finds it	searches for it now

A command entry opens the prompt showing the chosen line as its suggestion: Enter runs it, Up puts it in the line so you can edit it first. That falls out of Helix’s own prompt, which suggests and runs the newest : entry when the line is empty, so pulling one to the front is all this has to do.

Configure

Optional, after the require:

(previously-configure!
  (hash 'watch (list #\" #\a #\b) ; registers to capture yanks from
        'cap 50 ; entries kept per register
        'commands? #true ; include the : history
        'searches? #true)) ; include the / history

Any subset of the keys will do. The defaults are the yank register plus a-z, 100 entries per register, and both histories included.

Keymap

(require "helix/keymaps.scm")
(require "previously.hx/previously.scm")

(keymap (global)
  (normal
    (C-p ":previously"))
  (select
    (C-p ":previously")))

Known limitations

• A command entry cannot be run without opening the prompt. Steel has no binding for running an arbitrary typed line, so Alt-Enter on a : entry does what Enter does. Helix’s suggest-and-run behaviour makes that one keystroke rather than a shortfall, but it is still a prompt you have to confirm.
• A yank to a register outside the watch list is invisible. Nothing is captured that was not being watched at the time.
• Which register a yank targeted cannot be recovered. Helix take()s editor.selected_register before the command runs, so during the capture hook because the plug-in saw you type "b.
• + and * are never watched. Reading either calls the system clipboard provider, so watching them would reach for the clipboard after every yank.
• Alt-Enter pastes through the default yank register. Steel cannot set the pending register, so an immediate paste has to write where p reads. Enter stages to the entry’s own register and leaves the default alone.
• % starts a column filter. A literal % in a value, in a printf format or a SQL LIKE or a CSS unit, has to be typed \% to be searched for. Helix’s own pickers read % the same way.
• In-memory only. Matching Helix, which persists neither : history nor registers.

Tests

steel-test](https://github.com/waddie/steel-test⁠) in ~/.steel/cogs:

sh tests/run-all.sh

The capture hook and the picker require Helix modules, which cannot load under the bare steel CLI, so they are verified in the editor rather than in the suite.

Licence

AGPL-3.0. See LICENSE⁠.