lua switch

switch.lua

local Switch = {
  __tostring = function(self)
    return string.format('%s (strict: %s)', tostring(self.expression), tostring(self.strict))
  end
}
Switch.__index = Switch

function Switch:new(expression, strict)
  if type(strict) ~= 'boolean' then strict = true end
  local self = setmetatable({}, Switch)
  self.expression = expression
  self.strict = strict
  self.matched = false
  self.closed = false
  self.case = function (case, callback)
    if not self.closed and case == self.expression then
      self.matched = true
      if self.strict then self.closed = true end
      callback()
    end
  end
  self.default = function (callback)
    if not self.closed and not self.matched then
      if self.strict then self.closed = true end
      callback()
    end
  end
  return self
end

--------------------------------------------------

local check = 1;

local isOne = function ()
  print('is one')
end
local isTwo = function ()
  print('is two')
end
local default = function ()
  print('default')
end

local switch = Switch:new(check, false);
print('switch expression: ' .. tostring(switch))
switch.case('1', isOne)
switch.case(1, isOne)
switch.case(2, isTwo)
switch.default(default)
switch.case(1, isOne)
switch.case(2, isTwo)
switch.default(default)