pipeline.lua

-- Run a series of functions as a pipeline - each returning the next's arguments.
--
-- The first function will be ran immediately
--
-- @param interval Time between pipelines
-- @param funcs A list of functions, each one of the form function(...)
--              where ... is returned by the previous function.
-- @param params Optional, a list of arguments to pass to the first function
local function pipeline(interval, funcs, params)
	if funcs[1] ~= nil then
		params = table.pack(funcs[1](table.unpack(params)))
	end

	table.remove(funcs, 1)

	if #funcs > 0 then
		minetest.after(interval, pipeline, interval, funcs, params)
	end
end


-- Run a series of functions as a pipeline - each returning the next's arguments.
-- Player is injected as the first argument in functions.
--
-- The first function will be ran immediately
--
-- @param name Player name
-- @param interval Time between pipelines
-- @param funcs A list of functions, each one of the form function(player, ...)
--              where ... is returned by the previous function.
-- @param params Optional, a list of arguments to pass to the first function
local function pipeline_plr(name, interval, funcs, params)
	if funcs[1] ~= nil then
		local player = minetest.get_player_by_name(name)
		if not player then
			return
		end
		table.insert(params, 1, player)

		params = table.pack(funcs[1](table.unpack(params)))
	end

	table.remove(funcs, 1)

	if #funcs > 0 then
		minetest.after(interval, pipeline_plr, name, interval, funcs, params)
	end
end

zexample.lua

pipeline(1, {
	function()
		return 5.3	
	end,
	
	function(x)
		return 2*x
	end,
		
	math.round,
		
	nil, -- skip a step, ie: 2xInterval is between above and below functions
		
	function(x)
		return x*x, x*x*x
	end,
		
	function(x, y)
		return "X is: " .. x .. ", y is: " .. y
	end,
		
	print
})