Visual mode snippet expansion

[jandamm]

I'm currently migrating from UltiSnips.
It is possible to use $VISUAL there which is the text which was selected when triggering the snippet:
You select text, type an expansion keystroke, type the snippet and then again the keystroke (in insert)
Then the snippet is expanded and every appearance of $VISUAL is replaced. Not literally - using VISUAL as a placeholder was supported as well.

Reading the docs from Microsoft $TM_SELECTED_TEXT should be the equivalent. But I haven't got it to work yet.
Is this supported yet?

[hrsh7th]

You can use this solution.

TM_SELECTED_TEXT;log|<Plug>(vsnip-expand)

In this case, TM_SELECTED_TEXT behaves like $VISUAL or $TM_SELECTED_TEXT.

When you want to behave like ultisnips, please heads up ultisnips solution (I don't know ultisnips's $VISUAL workflow.)

Thanks.

[jandamm]

Assuming these mapping

imap <expr> <C-l>   vsnip#available(1)  ? '<Plug>(vsnip-expand-or-jump)' : '<C-l>'
smap <expr> <C-l>   vsnip#available(1)  ? '<Plug>(vsnip-expand-or-jump)' : '<C-l>'

I would expect the following:

ihello<ESC>vb<C-l>
I entered stored 'hello' as $TM_SELECTED_TEXT and I'm still in insert.

abc<C-l>
I expand the snippet 'abc' where $TM_SELECTED_TEXT is 'hello'.

My use case is selecting text visually, and wrap it in a snippet.
Mostly selecting autocmd ... and quickly wrap it in an augroup with a snippet.

[jandamm]

Actually the UltiSnips smap ... expand_or_jump is more complicated.

From what I've gathered this is the logic:

Is the selected text a snippet -> expand
Is cursor in an expanded snippet -> jump
else -> set selected text to $VISUAL

[hrsh7th]

Hm... Indeed, My provided solution does not support the your case (e.g. wrap by augroup etc).

OK, I will consider it.

Now, I have a question.
When expanding snippet on visual mode by ultisnips, how choose snippet from many candidates?
My understanding is that has no timing to choose snippet in this case.

[jandamm]

An example would be:

aug -> augroup ${1:auc} ${2:test} $0
auc -> hello

It then would work like this

aug<C-l> the snippet expands and auc is selected in select mode.
Pressing <C-l> again would then insert the snippet ('hello').

With your plugin: aug<C-l>auc<C-l> would be the same.

I do this because I only have to change auc to change the snippet and it is just referenced inside of aug instead of changing every snippet where I want to use it.

[jandamm]

I think a good addition would be <plug>(vsnip-visual-expand) where the visual selection is checked instead of the chars left to the cursor. Also the availability check would need to be updated/added for visual.

[hrsh7th]

I might misunderstand what you said.

Currently, IMO, I can't think your suggestion is useful...

For example, the above case should be enough aug -> augroup hello ${2:test} $0.

---

But I think we should implement visual snippet expansion as below behavior.

{
  "prefix": "wrap-tag",
  "body": [
    "<${1:tag}>",
    "\t$TM_SELECTED_TEXT",
    "</${1}>"
  ]
}

If it implemented, we can wrap HTML element by select&expand wrap-tag snippet in visual-mode.

[jandamm]

The idea why I used ${1:auc} instead of hello was that when I change hello to hi i would have to change both aug and auc. Of course auc isn't just hello and has many tabstops of its own.
autocmd ${1:${2:VimEnter} ${3:*}} $0

It is a way to include another snippet. It isn't something that cannot be achieved otherwise but reduces copy&paste.

[hrsh7th]

vsnip has nested placeholder feature so your recent example already supported now, I think.

{
  "aug": {
    "prefix": ["aug"],
    "body": ["autocmd ${1:${2:VimEnter} ${3:*}} $0"]
  }
}

This snippet works fine as you expected.

[jandamm]

How would I use wrap-tag?
Select it, press expand, type wrap-tag and press expand again?

[hrsh7th]

Currently, vsnip can't expand wrap-tag on visual-mode.

So we should implement mapping that add the ability to choose snippet on visual-mode.

[jandamm]

Yes the nested placeholders work fine.

I would want to use nested snippets,` like this:

{
  "aug": {
    "prefix": ["aug"],
    "body": ["something", "autocmd ${1:${2:VimEnter} ${3:*}} $0", "Else"]
  },
  "auc": {
    "prefix": ["auc"],
    "body": ["autocmd ${1:${2:VimEnter} ${3:*}} $0"]
  }
}

Now I have "autocmd ${1:${2:VimEnter} ${3:*}} $0" twice and changing it would require changing aug and auc.

Ideally aug would have this body:
"body": ["something", "$auc", "Else"]
Where $auc is replaced with the auc snippet.

[hrsh7th]

Probably I understood what you want.

Hm... I think it should not support vsnip itself.
But vsnip has vsnip#anonymous API so I provide the way to enable it for you, please wait.

[jandamm]

My idea was to use the visual selection as l:before_text in vsnip#get_context().

[jandamm]

The select mode mapping I was looking for is this:

func Reselect()
        return "\<ESC>gv\<C-g>\<C-l>"
endfunc

smap  <C-l>   <C-g>o<ESC>a<C-r>=(vsnip#available(1) && !vsnip#expand())  ? '' : Reselect() <CR>

[jandamm]

I checked what UltiSnips does in the visual mode mapping:

:call UltiSnips#SaveLastVisualSelection()<cr>gvs

In vsnips this would mean that this saves the currently selected text in the current context and provides this along with the next expanded snippet as $TM_SELECTED_TEXT.

[hrsh7th]

Which do you hope the <Plug>(vsnip-select-on-visual) or <Plug>(vsnip-expand-on-visual)?

I feel we talking about the two different feature.

Or, we talking about just the one feature if so, I want to understand it.

[jandamm]

I think it's two features:

a) use visual selection in snippets as $TM_SELECTED_TEXT
b) expand snippets from select mode

a) this is how UltiSnips does it: #49 (comment)
There is a mapping to store the text from visual mode and then use it for the next snippet.

b) I figured out how to do this without any change of your plugin:
#49 (comment)

[jandamm]

I believe vsnip#selected_text('Text') does what I'm looking for.

I'll test a bit and then report back.

[jandamm]

I got it working.
I'm busy right now but I'll do a write up soon.

Would you accept a PR which makes this feature discoverable and makes it easier to use it? Wouldn't change the API only add better support for the mappings.

[hrsh7th]

My random thought are

• It will be good to implement the 'b' feature in vsnip

  • I think that' better to add smap <Plug>(vsnip-expand) but <Plug>(vsnip-expand-or-jump) is not.

• I think the 'a' feature is very useful

  • But I couldn't think good interface...

[jandamm]

I have a somewhat working proof of concept. I'll create a PR when I've cleaned up.

[jandamm]

I've created two PRs one for a) and one for b).