Neovim buffer -> Rust Playground

rust_playground.lua

function rust_playground(opts)
  ---@diagnostic disable-next-line: redefined-local
  local opts = opts or {}
  local copy = opts.copy or false
  local open = opts.open or false
  local char_to_hex = function(c)
    return string.format('%%%02X', string.byte(c))
  end

  local function urlencode(url)
    if url == nil then
      return
    end
    url = url:gsub('\n', '\r\n')
    url = url:gsub('([^%w ])', char_to_hex)
    url = url:gsub(' ', '+')
    return url
  end

  local lines = vim.api.nvim_buf_get_lines(0, 0, -1, false)
  local text = table.concat(lines, '\n')
  local encoded = urlencode(text)

  local root_url = 'https://play.rust-lang.org/'
  local opts = {
    'version=stable',
    'mode=debug',
    'edition=2021',
    'code=' .. encoded,
  }

  local final_url = root_url .. '?' .. table.concat(opts, '&')
  if open then
    vim.fn.system({ 'open', final_url })
  end
  if copy then
    vim.cmd("let @*=trim('" .. final_url .. "')")
  end

  if not open and not copy then
    print(final_url)
  end

  return final_url
end