Preliminaries

Recipies assume the following namespace aliases:

[lambdaisland.witchcraft :as wc]
[lambdaisland.witchcraft.cursor :as c]

Keep it always day

Day follows night and night follows day, the same is true in Minecraft. But when you're working on a great build it can be a bit annoying to have to continue under the cover of darkness.

When the sun starts setting it's easy enough to skip through the night by resetting the clock:

(wc/set-time 0)

But even that gets tedious. Instead you can use this recipe to automatically flip back to the morning as soon as it starts getting late.

(future
  (while true
    (Thread/sleep 5000)
    (when (< 13000 (wc/time))
      (wc/set-time 0))))

At the heart of this is this simply when condition

(when (< 12000 (wc/time))
  (wc/set-time 0))

Time in Minecraft passes exactly 72 times faster than in real life, which means 24 "hours" in Minecraft equals 20 minutes in real life. The number you get from wc/time is the current time of day measured in "ticks", with a Minecraft day containing 24000 of these ticks. When that time is half up, at 12000 ticks, it's starting to turn night, so it's time to set it back to 0, the start of the day.

We do this in an infinite (while true ,,,) loop, and add a little (Thread/sleep ,,,) to wait a few seconds between each check.

But this infinite loop never ends. If we do that in a REPL then that's the end of the conversation, there's nothing else we can do after that. To prevent locking up the REPL like that you can run this code on a separate "thread", that's what future is for.