Clock

--Alias
--Pattern: ^setTime (\d+):(\d+) (\w+)$
set_time(matches[2], matches[3], matches[4])

--Timer
if min == nil then
    min = 0;
end
if hr == nil then
    hr = 0;
end

min = min + 1;
if min == 60 then
    min = 0;
    hr = hr + 1;
    if hr == 24 then
        hr = 0;
    end
end

--Script
function set_time(shr, smin, sdot)
    local h = tonumber(shr);
    if sdot == "AM" and h == 12 then
        h = 0;
    elseif sdot == "PM" and h ~= 12 then
        h = h + 12;
    end
    hr = h;
    min = tonumber(smin);
end

function write_time()
    local s;
    local shr;
    local smin;
    local sdot;

    if hr < 12 then
        sdot = "am";
    else
        sdot = "pm";
    end

    if hr == 0 then
        shr = "12"
    elseif hr > 12 then
        shr = hr - 12
    else
        shr = hr
    end

    if min < 10 then
        smin = "0" .. min;
    else
        smin = min;
    end

    s = "Time is " .. shr .. ":" .. smin .. " " .. sdot;
    return s;
end