First functional version

init.lua

@@ -0,0 +1,85 @@
+local Tactree = {}
+local Registry = {}
+
+local function NodeStart(node, args)
+	-- abort if started
+	if node.data then return end
+
+	node.data = node.parent and node.parent.data or args
+	node:_start()
+end
+
+local function NodeUpdate(node)
+	-- abort if not started
+	if not node.data then return end
+
+	local result = node:_tick()
+
+	if type(result) == 'boolean' then
+		node:_finish()
+
+		node.data = nil
+	end
+
+	return result
+end
+
+local function default_impl(node) end
+function Tactree.Node(name)
+	return function(t)
+		if Registry[name] then
+			error('node with name \'' .. name .. '\' already exists.',  2)
+		else
+			Registry[name] = {}
+		end
+
+		local node_type = Registry[name]
+
+		local tick = t.tick or t[1]
+		if type(tick) ~= 'function' then error('no tick function supplied', 2) end
+
+		node_type._tick = tick
+		node_type._start = type(t.start) == 'function' and t.start or default_impl
+		node_type._finish = type(t.finish) == 'function' and t.finish or default_impl
+	end
+end
+
+function Tactree.Tree(name)
+	if not Registry[name] then error('no such node \'' .. name .. '\'', 2) end
+
+	local node = setmetatable({}, { __index = Registry[name] })
+	node.children = {}
+	node.start = NodeStart
+	node.update = NodeUpdate
+
+	return function(children)
+		if type(children) == 'table' then
+			for _, child in ipairs(children) do
+				if type(child) == 'string' then
+					child = Tactree.Tree(child)
+				elseif type(child) ~= 'table' then
+					error('invalid child type: ' .. type(child), 2)
+				end
+
+				child.parent = node
+				table.insert(node.children, child)
+			end
+		end
+
+		return node
+	end
+end
+
+--[[
+	Tactree.Node 'Find nearest object' { function (node) ... end }
+	Tactree.Node 'Pick up object' { function (node) ... end}
+	Tactree.Node 'Move' { function (node) return node.data.creature:move(node.data.tx, node.data.ty, dt) end }
+
+	local t = Tactree.Tree 'Sequence' { 'Find nearest object', 'Move', 'Pick up object' }
+
+	t:start(...)
+
+	t:update()
+]]--
+
+return Tactree