require 'class'

str  = class("str")

function str:__init__(value)
    self.value = value
    end

function str:__add(b)
    local value = ""
    if self.value then
        value = value .. self.value
        end
        
    if b.value then
        value = value .. b.value
        end
        
    return str(value)
    end

function str:__str()
    return self.value
    end
    
function str:__mod(value)
    if value.__class__ == tuple then        
        local lua_params = {}
        
        for k, v in pairs(value.value) do                
            if type(v) == "table" and v.__class__ == str then
                table.insert(lua_params, v.value)
            else
                table.insert(lua_params, v)
                end
            end
            
        return str(string.format(self.value, table.unpack(lua_params)))
        end
    
    if value.__class__ == str then            
        return str(string.format(self.value, value.value))
        end        
    end