【入门夯实】Lua堆叠合并：仓库同物叠加的计数归并

local function stack(items)
    local out = {}
    for _, it in ipairs(items) do
        out[#out + 1] = it           -- 原样搬，同物各占一格
    end
    return out
end

local function stack(items)
    local out, n = {}, 0
    for _, it in ipairs(items) do
        local slot = out[it.id]
        if slot then
            slot.count = slot.count + it.count   -- 同id累加
        else
            n = n + 1
            out[it.id] = {id = it.id, count = it.count}
        end
    end
    return out, n
end
local _, n = stack(BAG)
sendmsg(actor, 1, "裁决之杖仓库堆叠后 " .. n .. " 种")