fixed cc shop (1.21.1)

function exchange(list,y,page)
    w,h = term.getSize()
    y=y+(h-1)*(page-1)
    local l = list[y]
    if y<=#list then
        local r,s = commands.clear("@p "..l[1].." "..l[2])
        local n = tonumber(string.match(s[1], "%s%d+%s"))
        if not r or n~=l[2] then
            commands.tellraw("@p {\"text\":\"Insufficient items.\",\"color\":\"red\"}")
            if n then commands.give("@p "..l[1].." "..n) end
        else
            commands.tellraw("@p {\"text\":\"Success!\",\"color\":\"green\"}")
            commands.give("@p "..l[3].." "..l[4])
        end
    end
end
function draw(list,page)
    term.redirect(peripheral.wrap("top"))
    peripheral.wrap("top").setTextScale(0.5)
    term.clear()
    term.setCursorPos(1,1)
    w,h = term.getSize()
    pages = 1
    if h>#list then
        pages = math.floor(#list/(h-1))
    end
    for i=1+(h-1)*(page-1),(h-1)*page do
        if i>#list then break end
        print(list[i][2].." "..list[i][1].." -> "..list[i][4].." "..list[i][3])
    end
    term.setCursorPos(1,h)
    write("<<<")
    term.setCursorPos(math.floor(w/2),h)
    write(page)
    term.setCursorPos(w-2,h)
    write(">>>")
end
--------------+
page = 1   --+#
table = {} --+#
--------------+
table[1] = {"minecraft:polished_diorite",1,"minecraft:stone",6}
table[2] = {"minecraft:stone",2,"minecraft:dirt",1}
---------------
draw(table,page)
while true do
    name,side,x,y = os.pullEvent("monitor_touch")
    w,h = term.getSize()
    if y<h then
        exchange(table,y,page)
    else
        if x<w/2 then
            page=page-1
            if page<1 then
                page = math.ceil(#table/(h-1))
            end
        else
            page=page+1
            if page>math.ceil(#table/(h-1)) then
                page = 1
            end
        end
    end
    draw(table,page)
end