---@diagnostic disable: discard-returns

local Character = {}

---@type table<integer, string>
Character.alpha = {}
string.gsub('abcdefghijklmnopqrstuvwxyz', '.', function(char)
  Character.alpha[string.byte(char)] = char
end)

---@type table<integer, string>
Character.digit = {}
string.gsub('1234567890', '.', function(char)
  Character.digit[string.byte(char)] = char
end)

---@type table<integer, string>
Character.white = {}
string.gsub(' \t\n', '.', function(char)
  Character.white[string.byte(char)] = char
end)

---Return specified byte is alpha or not.
---@param byte integer
---@return boolean
function Character.is_alpha(byte)
  return Character.alpha[byte] ~= nil or Character.alpha[byte + 32] ~= nil
end

---Return specified byte is digit or not.
---@param byte integer
---@return boolean
function Character.is_digit(byte)
  return Character.digit[byte] ~= nil
end

---Return specified byte is alpha or not.
---@param byte integer
---@return boolean
function Character.is_alnum(byte)
  return Character.is_alpha(byte) or Character.is_digit(byte)
end

---Return specified byte is white or not.
---@param byte integer
---@return boolean
function Character.is_white(byte)
  return Character.white[byte] ~= nil
end

---Return specified byte is symbol or not.
---@param byte integer
---@return boolean
function Character.is_symbol(byte)
  return not Character.is_alnum(byte) and not Character.is_white(byte)
end

return Character