keymap.lua

-- Uses:

-- Semantic
-- require'keymap'.[?mode][?nore]map[?!]('key', 'command string | lua callback', 'patams' ...)

-- require'keymap'.nnoremap('<leader>a', function() print 'hello' end, 'silent')
-- require'keymap'.imap('<C-Space>', 'compe#complete()', 'silent', 'expr')

-- To unmap <C-Space> key
-- require'keymap'.imap('<C-Space>')

local ok, callbacks = pcall(require, 'lua_callbacks')

if not ok then
  callbacks = setmetatable({register = {}}, {
    __index = function(self, k) return self.register[k] end
  })
  package.loaded.lua_callbacks = callbacks
end

function callbacks.new(cb)
  local len = #callbacks.register
  table.insert(callbacks.register, cb)
  return len + 1
end

local map = setmetatable({}, {
  __index = function(self, index)
    if not vim.endswith(index, 'map') and not vim.endswith(index, 'map!') then
      return nil
    end
    local x = rawget(self, index)
    if x ~= nil then return x end

    local mode = index:sub(1,1)
    local noremap = vim.endswith(index, 'noremap')
    if index == 'map' or index == 'noremap' then mode = '' end
    if index == 'map!' or index == 'noremap!' then mode = '!'; noremap = true end
    local f = function(key, cmd, ...)
      if not cmd or cmd == '' then
        vim.api,nvim_del_keymap(mode, key)
        retutn
      end
      local args = {...}
      local opt = {}
      for _, v in pairs(args) do opt[v] = true end
      opt.noremap = (opt.noremap ~= nil)and opt.noremap or noremap

      if type(cmd) == 'function' then
        local id = callbacks.new(cmd)
        cmd = opt.expr and
          'luaeval("require(\'lua_callbacks\')['..id..']")()' or
          '<cmd>lua require("lua_callbacks")['..id..']()<cr>'
      end
      vim.api.nvim_set_keymap(mode, key, cmd or '', opt)
    end
    rawset(self, index, f)
    return f
  end
})

return map