Rename 'context' to 'world'

src/world.lua

@@ -0,0 +1,288 @@
+--- World
+
+local PATH = (...):gsub('%.[^%.]+$', '')
+
+local Type   = require(PATH..".type")
+local List   = require(PATH..".list")
+
+local World = {}
+World.__index = World
+
+--- Creates a new World.
+-- @return The new World
+function World.new()
+   local world = setmetatable({
+      entities = List(),
+      systems  = List(),
+      events   = {},
+
+      marked   = {},
+      removed  = {},
+
+      __isWorld = true,
+   }, World)
+
+   return world
+end
+
+--- Adds an Entity to the World.
+-- @param e The Entity to add
+-- @return self
+function World:addEntity(e)
+   if not Type.isEntity(e) then
+      error("bad argument #1 to 'World:addEntity' (Entity expected, got "..type(e)..")", 2)
+   end
+
+   self:onEntityAdded(e)
+
+   e.worlds:add(self)
+   self.entities:add(e)
+   self:checkEntity(e)
+
+   return self
+end
+
+--- Marks an Entity as removed from the World.
+-- @param e The Entity to mark
+-- @return self
+function World:removeEntity(e)
+   if not Type.isEntity(e) then
+      error("bad argument #1 to 'World:removeEntity' (Entity expected, got "..type(e)..")", 2)
+   end
+
+   self.removed[#self.removed + 1] = e
+
+   return self
+end
+
+function World:markEntity(e)
+   if not Type.isEntity(e) then
+      error("bad argument #1 to 'World:markEntity' (Entity expected, got "..type(e)..")", 2)
+   end
+
+   self.marked[#self.marked + 1] = e
+
+   return self
+end
+
+--- Checks an Entity against all the systems in the World.
+-- @param e The Entity to check
+-- @return self
+function World:checkEntity(e)
+   if not Type.isEntity(e) then
+      error("bad argument #1 to 'World:checkEntity' (Entity expected, got "..type(e)..")", 2)
+   end
+
+   for i = 1, self.systems.size do
+      self.systems:get(i):__check(e)
+   end
+
+   return self
+end
+
+--- Completely removes all marked Entities in the World.
+-- @return self
+function World:flush()
+   while #self.marked > 0 do
+      local marked = self.removed
+      self.removed  = {}
+
+      for i = 1, #marked do
+         local e = marked[i]
+
+         e.Worlds:apply()
+         e.Worlds:checkEntity(e)
+      end
+   end
+
+   while #self.removed > 0 do
+      local removed = self.removed
+      self.removed  = {}
+
+      for i = 1, #removed do
+         local e = removed[i]
+
+         e.worlds:remove(self)
+         self.entities:remove(e)
+
+         for j = 1, self.systems.size do
+            self.systems:get(j):__remove(e)
+         end
+
+         self:onEntityRemoved(e)
+      end
+   end
+
+   for i = 1, self.systems.size do
+      local system = self.systems:get(i)
+      system:flush()
+      system:clear()
+   end
+
+   return self
+end
+
+--- Adds a System to the World.
+-- @param system The System to add
+-- @param eventName The Event to register to
+-- @param callback The function name to call. Defaults to eventName
+-- @param enabled If the system is enabled. Defaults to true
+-- @return self
+function World:addSystem(system, eventName, callback, enabled)
+   if not Type.isSystem(system) then
+      error("bad argument #1 to 'World:addSystem' (System expected, got "..type(system)..")", 2)
+   end
+
+   if system.__World and system.__World ~= self then
+      error("System already in World '" ..tostring(system.__World).."'")
+   end
+
+   if not self.systems:has(system) then
+      self.systems:add(system)
+      system.__World = self
+
+      system:addedTo(self)
+   end
+
+   if eventName then
+      self.events[eventName] = self.events[eventName] or {}
+
+      local i = #self.events[eventName] + 1
+      self.events[eventName][i] = {
+         system   = system,
+         callback = callback or eventName,
+         enabled  = enabled == nil or enabled,
+      }
+
+      if enabled == nil or enabled then
+         system:enabledCallback(callback or eventName)
+      end
+   end
+
+   local e
+   for i = 1, self.entities.size do
+      e = self.entities:get(i)
+
+      self:checkEntity(e)
+   end
+
+   return self
+end
+
+--- Enables a System in the World.
+-- @param system The System to enable
+-- @param eventName The Event it was registered to
+-- @param callback The callback it was registered with. Defaults to eventName
+-- @return self
+function World:enableSystem(system, eventName, callback)
+   if not Type.isSystem(system) then
+      error("bad argument #1 to 'World:enableSystem' (System expected, got "..type(system)..")", 2)
+   end
+
+   return self:setSystem(system, eventName, callback, true)
+end
+
+--- Disables a System in the World.
+-- @param system The System to disable
+-- @param eventName The Event it was registered to
+-- @param callback The callback it was registered with. Defaults to eventName
+-- @return self
+function World:disableSystem(system, eventName, callback)
+   if not Type.isSystem(system) then
+      error("bad argument #1 to 'World:disableSystem' (System expected, got "..type(system)..")", 2)
+   end
+
+   return self:setSystem(system, eventName, callback, false)
+end
+
+--- Sets a System 'enable' in the World.
+-- @param system The System to set
+-- @param eventName The Event it was registered to
+-- @param callback The callback it was registered with. Defaults to eventName
+-- @param enable The state to set it to
+-- @return self
+function World:setSystem(system, eventName, callback, enable)
+   if not Type.isSystem(system) then
+      error("bad argument #1 to 'World:setSystem' (System expected, got "..type(system)..")", 2)
+   end
+
+   callback = callback or eventName
+
+   if callback then
+      local listeners = self.events[eventName]
+
+      if listeners then
+         for i = 1, #listeners do
+            local listener = listeners[i]
+
+            if listener.system == system and listener.callback == callback then
+               if enable and not listener.enabled then
+                  system:enabledCallback(callback)
+               elseif not enable and listener.enabled then
+                  system:disabledCallback(callback)
+               end
+
+               listener.enabled = enable
+
+               break
+            end
+         end
+      end
+   end
+
+   return self
+end
+
+--- Emits an Event in the World.
+-- @param eventName The Event that should be emitted
+-- @param ... Parameters passed to listeners
+-- @return self
+function World:emit(eventName, ...)
+   if not eventName or type(eventName) ~= "string" then
+      error("bad argument #1 to 'World:emit' (String expected, got "..type(eventName)..")")
+   end
+
+   self:flush()
+
+   local listeners = self.events[eventName]
+
+   if listeners then
+      for i = 1, #listeners do
+         local listener = listeners[i]
+
+         if listener.enabled then
+            listener.system[listener.callback](listener.system, ...)
+         end
+      end
+   end
+
+   return self
+end
+
+--- Removes all entities from the World
+-- @return self
+function World:clear()
+   for i = 1, self.entities.size do
+      self.entities:get(i):destroy()
+   end
+
+   self:flush()
+
+   return self
+end
+
+--- Default callback for adding an Entity.
+-- @param e The Entity that was added
+function World:onEntityAdded(e) -- luacheck: ignore
+end
+
+--- Default callback for removing an Entity.
+-- @param e The Entity that was removed
+function World:onEntityRemoved(e) -- luacheck: ignore
+end
+
+return setmetatable(World, {
+   __call = function(_, ...)
+      return World.new(...)
+   end,
+})