Redstone Port

The Redstone Port connects Lua to vanilla redstone. A program sets the signal on each of the port's six sides, so a piston, door, lamp or note block next to it follows the program. It also reads what arrives: a lever, a pressure plate, a tripwire hook, a button or a comparator.

The port looks like a Data Pipe block and joins the network on all six sides, like a pipe, so it can sit inside a run of pipes. A machine touching it joins the network too.

In a program

Sides are "north", "south", "east", "west", "up" and "down", as the world sees them.

local port = network.findByName("redstone_port_1")
local ok, who = port.claim()               -- true, or false and who holds it
port.setOutput("up", 15)                   -- or true; a piston above the port extends
print(port.getInput("north"))              -- 0 to 15
print(port.getBlock("up").properties.extended)

Function	Does	Returns
claim()	Makes this program the only one that may set signals. Never waits.	true, or false + who holds it
release()	Gives the port back and switches all signals off.	true, or false if this program did not hold it
isClaimed()		false, or true + who holds it
setOutput(side, level)	Sets the signal given on that side: 0 to 15, or true for 15, false for 0. An error without a claim.
getOutput(side)		the signal set on that side
getInput(side)	The signal arriving on that side. Needs no claim.	0 to 15
getBlock(side)	The block next to that side. Needs no claim.	{ name = "minecraft:piston", properties = { extended = true, facing = "up" } }

Rules

• A program must claim() the port before it sets a signal. Another program that tries gets false and who holds it. Reading needs no claim.

• Nothing is saved. A port gives nothing until a program says so. When the program that claimed it ends, is stopped or loses its box, the port lets go and all its signals go to 0, so a piston never stays out after its program.

• A port gives weak power, like a block of redstone: it drives what touches it, not what sits behind a solid block.

• A side the program drives reads 0 from getInput, because what comes back there is the port's own signal.

• A piston gives no signal. Read whether it is out with getBlock(side).properties.extended. Right after a signal changes, the piston may still be on its way, so wait a moment before reading it.

• A very short pulse (an observer's two ticks) can be missed if the program waits longer than that between reads. Levers, plates and buttons hold their state long enough.

Camouflage

Right-click a port with a block in your hand and it looks like that block. The item is not used up. Sneak-click with an empty hand to take the look off. Sneak-click with a block still places the block.

Only the look is copied: the port keeps its own hardness, sound and signals. Any block with an ordinary model works, glass and slabs too, but the port stays a full block, so the result may look odd. Logs show their bark on the sides. The look is saved with the port.

Recipe: Getting started.