Coroutine.bit

package:application/vnd.bitty-archive;
data:text/json;count=145;path=info.json;
{
  "id": 0,
  "title": "Basics/07. Coroutine",
  "description": "",
  "author": "Tony",
  "version": "1.0",
  "genre": "TUTORIAL",
  "url": ""
}
data:text/lua;count=747;path=class.lua;
--[[
Example for the Bitty Engine

Copyright (C) 2020 - 2024 Tony Wang, all rights reserved

Homepage: https://paladin-t.github.io/bitty/
]]

-- Declares a class.
function class(kls, base)
	if not base then
		base = { }
	end

	kls.new = function (...)
		local obj = { }
		setmetatable(obj, kls)
		if obj.ctor then -- `ctor` is short for "constructor", where you can initialize your instance.
			obj:ctor(...)
		end

		return obj
	end

	kls.__index = kls

	setmetatable(kls, base)

	return kls
end

-- Determines whether an object is instance of a specific class.
function is(obj, kls)
	if kls == nil then
		error('Invalid class.')
	end

	repeat
		if obj == kls then
			return true
		end
		obj = getmetatable(obj)
	until not obj

	return false
end

data:text/lua;count=1725;path=co.lua;
--[[
Example for the Bitty Engine

Copyright (C) 2020 - 2024 Tony Wang, all rights reserved

Homepage: https://paladin-t.github.io/bitty/
]]

require 'class'

-- Coroutine class.
Coroutine = class({
	_cos = nil,

	waitFor = function (sec)
		local start = DateTime.ticks()
		sec = DateTime.fromSeconds(sec)

		while DateTime.ticks() - start < sec do
			coroutine.yield()
		end
	end,

	ctor = function (self)
		self._cos = nil
	end,

	__len = function (self)
		return #self._cos
	end,

	count = function (self)
		return #self._cos
	end,
	empty = function (self)
		return self._cos == nil or #self._cos == 0
	end,
	clear = function (self)
		self._cos = nil

		return self
	end,

	start = function (self, co, ...)
		if type(co) == 'function' then
			co = coroutine.create(co)
		end

		if type(co) ~= 'thread' then
			error('Unexpected data: ' .. tostring(co) .. '.')
		end

		if self._cos == nil then
			self._cos = { }
		end
		table.insert(self._cos, co)

		if coroutine.status(co) ~= 'dead' then
			local ret, msg = coroutine.resume(co, ...)
			if not ret then
				error(msg)
			end
		end

		return self
	end,

	update = function (self, ...)
		if self._cos == nil or #self._cos == 0 then
			return false
		end

		local dead = nil
		for i = 1, #self._cos do
			local co = self._cos[i]
			if coroutine.status(co) ~= 'dead' then
				local ret, msg = coroutine.resume(co, ...)
				if not ret then
					error(msg)
				end
			end
			if coroutine.status(co) == 'dead' then
				if dead == nil then
					dead = { }
				end
				table.insert(dead, i)
			end
			if self._cos == nil then
				return false
			end
		end
		if dead ~= nil then
			for i = #dead, 1, -1 do
				table.remove(self._cos, dead[i])
			end
		end

		return true
	end
})

data:text/lua;count=1051;path=main.lua;
--[[
Example for the Bitty Engine

Copyright (C) 2020 - 2024 Tony Wang, all rights reserved

Homepage: https://paladin-t.github.io/bitty/
]]

require 'co' -- Require the updatable coroutine wrapper.

local co = nil
local acc = 0

function setup()
	co = Coroutine.new() -- Create a coroutine object.

	co:start( -- Start the coroutine with a yieldable function.
		function (n)
			coroutine.yield(n)
			acc = n

			while true do -- Loop forever.
				Coroutine.waitFor(1) -- Wait for 1 second.
				acc = acc + 1 -- Accumulate it.
			end
		end,
		42 -- Arguments will be passed to the function above.
	)

	co:start( -- Start the coroutine with another function.
		function ()
			for i = 1, 5 do
				print(i)
				coroutine.yield(i)

				Coroutine.waitFor(1)
			end

			print('End.')
		end
	)
end

function update(delta)
	co:update() -- Update coroutines.

	local canvasWidth, canvasHeight = Canvas.main:size()
	local textWidth, textHeight = measure(acc)
	local x, y = (canvasWidth - textWidth) * 0.5, (canvasHeight - textHeight) * 0.5
	text(acc, x, y)
end