a function to print calendars

functioncalendar.lua

local function cal(starts_on, days_in_month)
    local n = starts_on - 1   -- column number
    local s = { string.rep("   ",n) }
    for day = 1,days_in_month do
        s[#s+1] = string.format(" %2d", day)
        n = n + 1
        if n >= 7 then
            s[#s+1] = "\n"
            n = 0
        end
    end
    if n > 0 then s[#s+1] = "\n" end
    return table.concat(s,"")
end
print(cal(5,30))