A version of the `pairs` Lua function that ignores numeric keys

pairs_not_numeric.lua

-- Usage: for k, v in kpairs(t) do ... end
local function knext(t, index)
    local value
    repeat
        index, value = next(t, index)
    until type(index) ~= 'number'
    return index, value
end
function kpairs(t)
    return knext, t, nil
end

-- Coroutine version
-- Usage: for k, v in co_kpairs(t) do ... end
function co_kpairs(t)
    return coroutine.wrap(function()
        for k, v in pairs(t) do
            if type(k) ~= 'number' then coroutine.yield(k, v) end
        end
    end)
end