Lua 5.2 custom array demo

[steve donovan <steve.j.donovan@...>]

It isn't particularly useful, but notice __len and __ipairs;
definitely an advance!

local array = {}
local rawset,rawget,ipairs = rawset,rawget,ipairs
in array do
    function __len(t)
        return #t.store
    end
    function __newindex(t,i,val)
        rawset(t.store,i,val)
    end
    function __index(t,i)
        return rawget(t.store,i)
    end
    function __ipairs(t)
        return ipairs(t.store)
    end
end

function new_array ()
    return setmetatable({store={}},array)
end

t = new_array()

t[1] = 10
t[2] = 20

print(#t)

for i,v in ipairs(t) do print(i, v) end

=>
2
1       10
2       20

Of course, any mock-tables have to survive being passed to the table
functions, which traditionally do not cope well ;)

(__ipairs/__pairs is not currently documented)

steve d.