local string = _G.string or {};

function string.change(s, t)
    if not s or type (s) ~= 'string' then
        return 'N/A'
    end

    for w in s:gmatch ('${(%w+)}') do
        s = s:gsub ('${'..w..'}', tostring ((t and t[w]) or 'undefined'))
    end

    return s
end

return string;