Simple :sh command substitutions

[aikomastboom]

It would be nice to be able to reference editor information on the :sh line.

Things like for example:

subs	description
$fn	filename (= $bn.$ex)
$bn	basename
$ex	extension
$fp	full path
$rp	relative path (to .git root?)
$ln	line number

to be able to execute things like:

:sh gh browse $fn:$ln

Of course above example is just a starting point to get the idea across.

[the-mikedavis]

It's a bit of a nit but I'd prefer more explicit names like $file, $line rather than two-character shortcuts. They're not very discoverable and are only marginally easier to type

[aikomastboom]

Indeed, whole words as tokens is indeed nicer, especially when combined with completion to speed up the typing.

Also it occurred to me the $ prefix may not be such a great idea, as it commonly used by sh itself. What about # as a tokenizer?

• #line
• #filename
  Etc. (TBD)

[the-mikedavis]

I imagine this would be implemented by setting environment variables for the shell command and then the shell command would interpret them - so $var for unix-like and %var% or whatever it is for windows - rather than a search-and-replace or templating language rendered ahead of time.

[aikomastboom]

Ah, yes, of course we have full control over the env space at execution time.

Still would like to have some help typing the longer vars though ;)

[AceofSpades5757]

I think longer variable names also follows Helix' way of doing things. I imagine that aliases would be implemented in the future with more configuration options.

Instead of environment variables, configuration variables could be used as well, for the project/.helix directory.

[aikomastboom]

Revised table:

env	description
$HX_FILENAME	filename
$HX_BASENAME	basename
$HX_FILE_EXT	file extension
$HX_PATH	full absolute path
$HX_RELATIVE_PATH	relative path (to .git root? or $CWD)
$HX_LINE	line number
$HX_COLUMN	cursor pos (on line)

[the-mikedavis]

I think we should start small: we probably only need file, line and column. The others can be derived in the shell with basename/extname/dirname/pwd/etc (I'm sure windows has equivalents, right? 🙃)

[aikomastboom]

I would suggest keeping $HX_PATH as this is a known fact of the editor, not having it would add unneeded clutter to constructing an arbitrary command line.

[aikomastboom]

... (I'm sure windows has equivalents, right? 🙃)

🕵️‍♂️ No clue either, haven't used it in a long time.. but I certainly hope command.com got improved upon. 🤔 Is Cygwin still around?

[AceofSpades5757]

Windows has the capacity to derive the same values and Cygwin, or similar programs, are available. I'd recommend WSL if you need Linux capabilities, though, compared to Cygwin or other alternatives.

[devyn]

I kind of like the way Kakoune does it. They have interpolations like %val{bufname} (access a value) or %opt{filetype} (access an option), but some common things are also in registers, which Helix already supports, but they just have more of them. The % register contains the buffer name, so you can always <C-r> % to get the buffer name.

On that note I'd love to be able to access the regex captures that way too - registers 0-9 in Kakoune are used for the capture groups. So you can s pattern <ret> c <C-r> 1 <esc> to replace with capture group 1 for example.

[AceofSpades5757]

@devyn Ah, that's an interesting take on it. Looks pretty nice. I wonder if there's a common Rust library that essentially does the same thing.

Kakoune Commands (Prompt)
Kakoune Prompt Expansion

The only expansions I can think of with Vim is % and #, but I'm really not a fan of how unintuitive it feels. I'm sure there are other things that I'm simply not aware of, given the docs and implementation.