Expanding trailing closures

[wojciech-kulik]

Unfortunately, sourcekit-lsp by default suggests closure as a parameter. If you want to change it to a trailing closure, you need to manually edit the completion.

I managed to write a small function to transform it automatically. You just hit se and it's done:

trailing_closure.mov

-- closures.lua

local M = {}

function M.expand_swift_closure()
  local currentLine = vim.api.nvim_get_current_line()
  local closurePattern = "^(%s*)([^%(]*)%(([^%(]*), %w+%: %(([^%)]*)%) %-%> %([^%)]*%)%)"

  if not string.find(currentLine, closurePattern) then
    return
  end

  local padding, foo, params, closureParams = string.match(currentLine, closurePattern)
  local _, numberOfParams = string.gsub(closureParams, ",", "")
  local funcCall = padding .. foo .. "(" .. params .. ") { "
  local expandedClosure = funcCall

  if string.len(closureParams) > 0 then
    numberOfParams = numberOfParams + 1
  end

  for i = 1, numberOfParams do
    expandedClosure = expandedClosure .. (i > 1 and ", " or "") .. "param" .. i
  end

  if numberOfParams > 0 then
    expandedClosure = expandedClosure .. " in"
  end

  local newLines = {
    expandedClosure,
    padding .. "    ",
    padding .. "}",
  }

  local row = vim.api.nvim_win_get_cursor(0)[1]

  vim.api.nvim_buf_set_lines(0, row - 1, row, false, newLines)

  if numberOfParams > 0 then
    vim.api.nvim_win_set_cursor(0, { row, string.len(funcCall) })
  else
    vim.api.nvim_win_set_cursor(0, { row + 1, string.len(padding) + 5 })
  end
end

return M

And here is the binding:

vim.keymap.set("n", "se", M.expand_swift_closure, { desc = "Expand Swift Closure" })

[wojciech-kulik]

This issue no longer occurs with the latest sourcekit-lsp.