Constants in Lua

[Alienhead]

Easy way to force Lua into using CONSTANTS. Actually you can protect any table you create this way, doesn't have to be a table labled const.

 

const = {}

const.avar = 10

protect(const)

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

function protect(tbl)
    return setmetatable({}, {
        __index = tbl,
        __newindex = function(t, key, value)
            error("attempting to change constant " ..
                   tostring(key) .. " to " .. tostring(value), 2)
        end
    })
end