Migrate from LuaSnip

[amuller-maths]

Contributing guidelines

• I have read CODE_OF_CONDUCT.md

Module(s)

mini.keymap, mini.snippets

Question

I am trying to migrate my current setup to mini.nvim.

I often write documents in LaTeX format and rely heavily on LuaSnip to perform one of the following tasks:

• typing ;a and a snippet auto-expands to give \alpha (the same with ;b which gives \beta, etc.)
  Here is an exemple :

local s = ls.snippet
local sn = ls.snippet_node
local t = ls.text_node
local i = ls.insert_node
local f = ls.function_node
local d = ls.dynamic_node
local r = ls.restore_node

return {
s({ trig = ";a", snippetType = "autosnippet" }, {
    t "\\alpha",
  })
}

• a snippet is manually triggered after writing a regex and the expansion gives me a dynamic snippet that depends on the regex (for example, if I want to write a matrix, I can give its size as “parameters,” say 3x2, and I am given a snippet with 6 placeholders.

Here is an exemple:

local generate_matrix = function(args, snip)
  local rows = tonumber(snip.captures[2])
  local cols = tonumber(snip.captures[3])
  local nodes = {}
  local ins_indx = 1
  for j = 1, rows do
    table.insert(nodes, r(ins_indx, tostring(j) .. "x1", i(1)))
    ins_indx = ins_indx + 1
    for k = 2, cols do
      table.insert(nodes, t " & ")
      table.insert(nodes, r(ins_indx, tostring(j) .. "x" .. tostring(k), i(1)))
      ins_indx = ins_indx + 1
    end
    table.insert(nodes, t { "\\\\", "" })
  end
  -- fix last node.
  nodes[#nodes] = t "\\\\"
  return sn(nil, nodes)
end

return {
s(
    {
      trig = "([bBpvV])mat(%d+)x(%d+)([ar])",
      name = "[bBpvV]matrix",
      dscr = "matrices",
      regTrig = true,
      hidden = false,
    },
    fmta(
      [[
    \begin{<>}<>
    <>
    \end{<>}]],
      {
        f(function(_, snip)
          return snip.captures[1] .. "matrix"
        end),
        f(function(_, snip)
          if snip.captures[4] == "a" then
            local out = string.rep("c", tonumber(snip.captures[3]) - 1)
            return "[" .. out .. "|c]"
          end
          return ""
        end),
        d(1, generate_matrix),
        f(function(_, snip)
          return snip.captures[1] .. "matrix"
        end),
      }
    ),
    -- { condition = in_math, show_condition = in_math }
    { show_condition = in_math }
  ),
}

Is it possible to emulate such behavior with mini.snippets (with maybe the addition of other mini plugins) ?

[echasnovski]

• typing ;a and a snippet auto-expands to give \alpha (the same with ;b which gives \beta, etc.)

'mini.snippets' is not really designed to have autoexpand. Mostly because I think this is not really suitable for snippets and is somewhat of an abbreviations (:h abbreviations) territory.

However, just out of curiosity, I tried to do this in 'mini.snippets'. It is somewhat possible, but kind of not straightforward. Here is an example of full working setup:

• Set up 'mini.snippets':

  local snippets, config_path = require('mini.snippets'), vim.fn.stdpath('config')
  
  -- Load dedicated snippet files in buffers with 'tex' and 'plaintex' filetypes
  local latex_patterns = { 'latex/**/*.json', '**/latex.json' }
  local lang_patterns = { tex = latex_patterns, plaintex = latex_patterns }
  
  snippets.setup({
    snippets = {
      -- Can have global snippet file here, but it is not relevant to the repro
      -- snippets.gen_loader.from_file(config_path .. '/snippets/global.json'),
      snippets.gen_loader.from_lang({ lang_patterns = lang_patterns }),
    },
  })

• Create a buffer-local mapping for ; to automatically schedule expanding snippets after the next key press. For this, create the file '~/.config/nvim/after/ftplugin/plaintex.lua' (and/or different basename for the target filetype):

  -- Autoexpand on `;`. Outline:
  -- - Pressing `;` creates an `InsertCharPre` autocommand to wait for the next
  --   key press without side effects.
  -- - Pressing next key tries to automatically expand snippet via
  --   `MiniSnippets.expand()`.
  -- - Exiting Insert mode deletes the `InsertCharPre` autocommand to be able to
  --   press `<Esc>` and not have next key press autoexpand.
  
  -- NOTE: Needs `vim.schedule_wrap` because at the moment of `InsertCharPre`
  -- the line is not yet up to date.
  local expand_later = vim.schedule_wrap(function() MiniSnippets.expand() end)
  
  -- NOTE: Needs `vim.schedule_wrap` because at the moment of pressing `;`
  -- there will be an `InsertCharPre` event for that character. While the needed
  -- one is for the *next* character.
  local schedule_autoexpand = vim.schedule_wrap(function()
    local au_id = vim.api.nvim_create_autocmd('InsertCharPre', { once = true, callback = expand_later })
  
    local del_autocmd = function() pcall(vim.api.nvim_del_autocmd, au_id) end
    vim.api.nvim_create_autocmd('InsertLeave', { callback = del_autocmd })
  end)
  
  -- Make expression mapping for `;` to do something and return itself.
  -- This part can be done with 'mini.keymap', but there is no need for it.
  local make_autoexpand = function(key)
    return function()
      schedule_autoexpand()
      return key
    end
  end
  vim.keymap.set('i', ';', make_autoexpand(';'), { expr = true, buffer = 0 })

• Add your snippets in directories compatible with 'mini.snippets' setup in the first step. For example, in file '~/.config/nvim/after/snippets/latex.json':

  {
    "alpha": { "prefix": ";a", "body": "\\alpha" },
    "beta": { "prefix": ";b", "body": "\\beta" }
  }

Now opening a file named 'test.tex' and typing ;a should autoreplace it with \alpha.

[echasnovski]

• a snippet is manually triggered after writing a regex and the expansion gives me a dynamic snippet that depends on the regex (for example, if I want to write a matrix, I can give its size as “parameters,” say 3x2, and I am given a snippet with 6 placeholders.

It is also mostly possible with 'mini.snippets', but with a little bit different fundamental approach.

The 'mini.snippets' module only supports LSP syntax for snippets. But it supports dynamic [computation/preparation of snippets]. It is done on every expand and can leverage different types of snippets supplied in config.snippets.

What can be suitable here is a single function loader that is added only for dedicated LaTeX filetypes (like 'plaintex'). Here is a basic template that is meant to be put in '~/.config/nvim/after/ftplugin/plaintex.lua' file:

-- Create LaTeX only dynamic snippets
local dynamic_matrix_snippet = function()
  -- Get text to cursor's left and check if it matches the necessary pattern
  local line = vim.api.nvim_get_current_line()
  local col = vim.api.nvim_win_get_cursor(0)[2]
  local text_before_cursor = line:sub(1, col):match('%S*$')

  local prefix, rows, cols = text_before_cursor:match('([bBpvV]mat(%d+)x(%d+)[ar])$')
  if prefix == nil then return {} end

  -- Compute the body of LSP snippet based on the data from matched pattern
  -- TODO: Adjust this to return text for the actual matrix body.
  -- This is just a placeholder.
  local body = string.rep('a', rows) .. string.rep('b', cols)
  return { { prefix = prefix, body = body, desc = 'Dynamic matrix' } }
end
vim.b.minisnippets_config = { snippets = { dynamic_matrix_snippet } }

Now typing something like vmat3x2a and pressing <C-j> (to expand) replaces this text with aaabb.
I am not very well versed in LaTeX (and LuaSnip syntax), so I'd leave details of what the output needs to be as an exercise :)

[amuller-maths]

Thank you VERY MUCH, that answers both of my questions perfectly.

I am just a modest user of neovim, and I am very impressed by what can be done with this software and by your skills and mastery of the subject.

This motivates me to migrate completely to mini.nvim.

Keep up the good work !

[echasnovski]

You are too kind :)
Good luck with your Neovim and 'mini.nvim' journey!