Common class

--[[

    Common utilities
    Classes

--]]

common = common or {}

-- Lookup in list of tables
local function search(k, plist)
    for i=1, table.getn(plist) do
        local v = plist[i][k]
        if v ~= nil then return v end
    end
end

-- Define class with multiple inheritance
function common.newClass(...)
    local c = {}
    local parents = { ... }

    -- Class searches for each method
    -- in the list of its parents
    setmetatable(c, {
        __index = function(t, k)
            return search(k, parents)
        end
    })

    -- Prepare 'c' to be the metatable of its instances
    c.__index = c

    -- Define constructor for this new class
    function c:new(o)
        o = o or {}
        setmetatable(o, c)

        -- Call constructor
        if o.init then o:init() end

        return o
    end

    -- Return new class
    return c
end