【入门夯实】字符串反转：reverse的字节边界与倒序查找

local name = "裁决之杖"
local bad = string.reverse(name)
sendmsg(nil, 1, bad)

local function revSerial(s)
    return string.reverse(s)
end
local function revChinese(s)
    local chars = {}
    for ch in string.gmatch(s, ".[\128-\191]*") do
        chars[#chars + 1] = ch
    end
    local out = {}
    for i = #chars, 1, -1 do
        out[#out + 1] = chars[i]
    end
    return table.concat(out)
end

local sn = "20260924001"
sendmsg(nil, 1, "尾号校验：" .. string.reverse(string.sub(sn, -3)))

local function findLast(s, sub)
    local rs = string.reverse(s)
    local rsub = string.reverse(sub)
    local p = string.find(rs, rsub, 1, true)
    if not p then
        return nil
    end
    return #s - p - #sub + 2
end