MOUSE OPERATED MENU FUNCTION USAGE EXAMPLE

function menu(t,x,y,ht)
    local size={term.getSize()}
    ht=math.min(ht or 0,#t)
    local scrolled=0
    local scroll=false
    if #t>ht then scroll=true end
    local max=0
    for i=1,#t do
        max=math.max(max,#t[i])
    end

    while true do
        for i=1,(scroll and ht or #t) do
            term.setCursorPos(x,y+i-1)
            write(string.rep(' ',max))
        end
        for i=1,(scroll and ht or #t) do
            term.setCursorPos((scrolled>0 and i==1 and math.floor(max/2+x) or scrolled+ht<#t and i==ht and scroll and math.floor(max/2+x) or x),y+i-1)
            write(scrolled>0 and i==1 and '^' or scrolled+ht<#t and i==ht and scroll and 'v' or t[i+scrolled])
        end
        --if scroll then term.setCursorPos(x,y+ht-1) write('v') end
        local input={os.pullEvent()}
        if input[1]=='mouse_click' and input[2]==1 and input[3]>=x and input[3]<=x+max-1 and input[4]>=y and input[4]<=y+ht-1 then
            if scrolled>0 and input[4]==y then
                scrolled=scrolled-1
            elseif scrolled+ht<#t and scroll and input[4]==y+ht-1 then
                scrolled=scrolled+1
            else
                return t[input[4]+scrolled-y+1]
            end
        end
    end
end

term.clear()
print(menu({'111','222','333','444','555'},2,2,6))