Update to version 1.1-4.

Remove tiny.getSystemEntityCount because it's useless and deprecation is for chumps.

README.md

@@ -1,4 +1,7 @@
 # tiny-ecs #
+
+[![License](http://img.shields.io/badge/Licence-MIT-brightgreen.svg)](LICENSE)
+
 Tiny-ecs is an Entity Component System for lua that's simple, flexible, and useful.
 Because of lua's tabular nature, Entity Component Systems are a natural choice
 for simulating large and complex systems. For more explanation on Entity
@@ -75,7 +78,7 @@ Tiny-ecs is also on [Luarocks](https://luarocks.org/) and can be installed with
 ## Demo ##
 Check out the [demo](https://github.com/bakpakin/tiny-ecs/tree/demo-commandokibbles), a game
 originally written for Ludum Dare 32 with the theme 'An Unconventional Weapon'. The demo uses
-[LOVE](https://love2d.org/), an amazing game framework for lua.
+[LÖVE](https://love2d.org/), an amazing game framework for lua.
 
 ## Testing ##
 Tiny-ecs uses [busted](http://olivinelabs.com/busted/) for testing. Install and run
@@ -85,3 +88,4 @@ Tiny-ecs uses [busted](http://olivinelabs.com/busted/) for testing. Install and
 See API [here](http://bakpakin.github.io/tiny-ecs/doc/).
 For the most up-to-date documentation, read the source code, or generate the HTML
 locally with [LDoc](http://stevedonovan.github.io/ldoc/).
+See the original forum thread [here](https://love2d.org/forums/viewtopic.php?f=5&t=79937&p=182589).

config.ld

@@ -10,3 +10,4 @@ style = '!fixed'
 package = 'tiny-ecs'
 not_luadoc = true
 boilerplate = true
+no_return_or_parms = true

rockspecs/tiny-ecs-1.1-4.rockspec

@@ -0,0 +1,24 @@
+package = "tiny-ecs"
+version = "1.1-4"
+source = {
+    url = "git://github.com/bakpakin/tiny-ecs",
+    tag = "1.1-4"
+}
+description = {
+    summary = "Entity Component System for Lua.",
+    detailed = [[
+        Pure Lua implementation of an easy to use, compact, fast, and flexible
+        Entity Component System. Works well with Object Orientation.
+    ]],
+    homepage = "https://github.com/bakpakin/tiny-ecs",
+    license = "MIT"
+}
+dependencies = {
+    "lua >= 5.1"
+}
+build = {
+    type = "builtin",
+    modules = {
+        tiny = "tiny.lua"
+    }
+}

spec/tiny_spec.lua

@@ -215,6 +215,19 @@ describe('tiny-ecs:', function()
             assert.equals(1, world:getSystemIndex(oneTimeSystem))
         end)
 
+        it("Sorts Entities in Sorting Systems", function()
+            local sortsys = tiny.sortedProcessingSystem()
+            sortsys.filter = tiny.requireAll("vel")
+            function sortsys:compare(e1, e2)
+                return e1.vel.x < e2.vel.x
+            end
+            world:add(sortsys)
+            world:update(0)
+            assert.equals(sortsys.entities[1], entity2)
+            assert.equals(sortsys.entities[2], entity3)
+            assert.equals(sortsys.entities[3], entity1)
+        end)
+
     end)
 
 end)

tiny.lua

@@ -23,14 +23,13 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 -- @author Calvin Rose
 -- @license MIT
 -- @copyright 2015
-local tiny = { _VERSION = "1.1-3" }
+local tiny = { _VERSION = "1.1-4" }
 
 -- Local versions of standard lua functions
 local tinsert = table.insert
 local tremove = table.remove
 local tsort = table.sort
 local pairs = pairs
-local ipairs = ipairs
 local setmetatable = setmetatable
 local type = type
 local select = select
@@ -51,8 +50,8 @@ local tiny_remove
 -- value indicating if the Entity should be processed by the System.
 --
 -- Filters must be added to Systems by setting the `filter` field of the System.
--- Filter's returned by `tiny.requireAll` and `tiny.requireAny` are immutable
+-- Filter's returned by tiny-ecs's Filter functions are immutable and can be
--- and can be used by multiple Systems.
+-- used by multiple Systems.
 --
 --    local f1 = tiny.requireAll("position", "velocity", "size")
 --    local f2 = tiny.requireAny("position", "velocity", "size")
@@ -88,7 +87,6 @@ local tiny_remove
 
 --- Makes a Filter that selects Entities with all specified Components and
 -- Filters.
--- @param ... List of required Components and other Filters.
 function tiny.requireAll(...)
     local components = {...}
     local len = #components
@@ -110,7 +108,6 @@ end
 
 --- Makes a Filter that selects Entities with at least one of the specified
 -- Components and Filters.
--- @param ... List of required Components and other Filters.
 function tiny.requireAny(...)
     local components = {...}
     local len = #components
@@ -132,7 +129,6 @@ end
 
 --- Makes a Filter that rejects Entities with all specified Components and
 -- Filters, and selects all other Entities.
--- @param ... List of required Components and other Filters.
 function tiny.rejectAll(...)
     local components = {...}
     local len = #components
@@ -154,7 +150,6 @@ end
 
 --- Makes a Filter that rejects Entities with at least one of the specified
 -- Components and Filters, and selects all other Entities.
--- @param ... List of required Components and other Filters.
 function tiny.rejectAny(...)
     local components = {...}
     local len = #components
@@ -183,10 +178,15 @@ end
 --
 -- There are also a few other optional callbacks:
 --
---   * `function system:filter(entity)`
+--   * `function system:filter(entity)` - Returns true if this System should
---   * `function system:onAdd(entity)`
+-- include this Entity, otherwise should return false. If this isn't specified,
---   * `function system:onRemove(entity)`
+-- no Entities are included in the System.
---   * `function system:onModify(dt)`
+--   * `function system:onAdd(entity)` - Called when an Entity is added to the
+-- System.
+--   * `function system:onRemove(entity)` - Called when an Entity is removed
+-- from the System.
+--   * `function system:onModify(dt)` - Called when the System is modified by
+-- adding or removing Entities from the System.
 --
 -- For Filters, it is convenient to use `tiny.requireAll` or `tiny.requireAny`,
 -- but one can write their own filters as well. Set the Filter of a System like
@@ -201,11 +201,17 @@ end
 -- system is added to the World. A few are important, and few should be less
 -- commonly used.
 --
+--   * The `world` field points to the World that the System belongs to. Useful
+-- for adding and removing Entities from the world dynamically via the System.
 --   * The `active` flag is whether or not the System is updated automatically.
 -- Inactive Systems should be updated manually or not at all via
 -- `system:update(dt)`. Defaults to true.
 --   * The 'entities' field is an ordered list of Entities in the System. This
 -- list can be used to quickly iterate through all Entities in a System.
+--   * The `interval` field is an optional field that makes Systems update at
+-- certain intervals using buffered time, regardless of World update frequency.
+-- For example, to make a System update once a second, set the System's interval
+-- to 1.
 --   * The `indices` field is a table of Entity keys to their indices in the
 -- `entities` list. Most Systems can ignore this.
 --   * The `modified` flag is an indicator if the System has been modified in
@@ -219,20 +225,11 @@ end
 -- this key is considered a System rather than an Entity.
 local systemTableKey = { "SYSTEM_TABLE_KEY" }
 
--- Check if tables are systems.
+-- Checks if a table is a System.
 local function isSystem(table)
     return table[systemTableKey]
 end
 
---- Creates a default System.
--- @param table A table to be used as a System, or `nil` to create a new System.
--- @return A new System or System class
-function tiny.system(table)
-    table = table or {}
-    table[systemTableKey] = true
-    return table
-end
-
 -- Update function for all Processing Systems.
 local function processingSystemUpdate(system, dt)
     local entities = system.entities
@@ -258,24 +255,45 @@ local function processingSystemUpdate(system, dt)
     end
 end
 
---- Creates a Processing System.
+-- Sorts Systems by a function system.sort(entity1, entity2) on modify.
---
+local function sortedSystemOnModify(system, dt)
--- A Processing System iterates through its Entities in no particluar order, and
+    local entities = system.entities
--- updates them individually. It has two important fields:
+    local indices = system.indices
---
+    local sortDelegate = system.sortDelegate
---   * `function system:process(entity, dt)`
+    if not sortDelegate then
---   * `function system:filter(entity)`
+        local compare = system.compare
---
+        sortDelegate = function(e1, e2)
--- There are also a few other optional callbacks, including the optional
+            return compare(system, e1, e2)
--- callbacks in `tiny.system`:
+        end
---
+        system.sortDelegate = sortDelegate
---   * `function system:preProcess(entities, dt)`
+    end
---   * `function system:postProcess(entities, dt)`
+    tsort(entities, sortDelegate)
---
+    for i = 1, #entities do
--- @param table A table to be used as a System, or `nil` to create a new
+        local entity = entities[i]
--- Processing System.
+        indices[entity] = i
+    end
+end
+
+--- Creates a new System or System class from the supplied table. If `table` is
+-- nil, creates a new table.
+function tiny.system(table)
+    table = table or {}
+    table[systemTableKey] = true
+    return table
+end
+
+--- Creates a new Processing System or Processing System class. Processing
+-- Systems process each entity individual, and are usually what is needed.
+-- Processing Systems have three extra callbacks besides those inheritted from
+-- vanilla Systems.
+--     * `function system:preProcess(entities, dt)` - Called before iterating
+-- over each Entity.
+--     * `function system:process(entities, dt)` - Called for each Entity in
+-- the System.
+--     * `function system:postProcess(entity, dt)` - Called after iteration.
+-- Processing Systems have their own `update` method, so don't implement a
+-- a custom `update` callback for Processing Systems.
 -- @see system
--- @return A new Processing System or Processing System class
 function tiny.processingSystem(table)
     table = table or {}
     table[systemTableKey] = true
@@ -283,45 +301,31 @@ function tiny.processingSystem(table)
     return table
 end
 
--- Sorts Systems by a function system.sort(entity1, entity2) on modify.
+--- Creates a new Sorted System or Sorted System class. Sorted Systems sort
-local function sortedSystemOnModify(system, dt)
+-- their Entities according to a user-defined method, `system:compare(e1, e2)`,
-    local entities = system.entities
+-- which should return true if `e1` should come before `e2` and false otherwise.
-    local entityIndices = system.entityIndices
+-- Sorted Systems also override the default System's `onModify` callback, so be
-    local sortDelegate = system.sortDelegate
+-- careful if defining a custom callback. However, for processing the sorted
-    if not sortDelegate then
+-- entities, consider `tiny.sortedProcessingSystem(table)`.
-        local compare = system.compare
+-- @see system
-        sortDelegate = function(e1, e2)
+function tiny.sortedSystem(table)
-            compare(system, e1, e2)
+    table = table or {}
-        end
+    table[systemTableKey] = true
-        system.sortDelegate = sortDelegate
+    table.onModify = sortedSystemOnModify
-    end
+    return table
-    tsort(entities, sortDelegate)
-    for i = 1, #entities do
-        local entity = entities[i]
-        entityIndices[entity] = i
-    end
 end
 
---- Creates a Sorted Processing System. A Sorted System iterates through its
+--- Creates a new Sorted Processing System or Sorted Processing System class.
--- Entities in a specific order, and updates them individually. It has three
+-- Sorted Processing Systems have both the aspects of Processing Systems and
--- important methods:
+-- Sorted Systems.
---
---   * `function system:process(entity, dt)`
---   * `function system:compare(entity1, entity2)`
---   * `function system:filter(entity)`
---
--- Sorted Systems have the same optitonal callbacks as ProcessingSystems.
--- @param table A table to be used as a System, or `nil` to create a new
--- Sorted System.
 -- @see system
 -- @see processingSystem
--- @return A new Sorted System or Sorted System class
+-- @see sortedSystem
-function tiny.sortedSystem(table)
+function tiny.sortedProcessingSystem(table)
     table = table or {}
     table[systemTableKey] = true
     table.update = processingSystemUpdate
     table.onModify = sortedSystemOnModify
-    table.sort = sortedSystemOnModify
     return table
 end
 
@@ -339,10 +343,7 @@ local worldMetaTable
 
 --- Creates a new World.
 -- Can optionally add default Systems and Entities.
--- @param ... Systems and Entities to add to the World
--- @return A new World
 function tiny.world(...)
-
     local ret = {
 
         -- List of Entities to add
@@ -376,14 +377,11 @@ function tiny.world(...)
     tiny_manageEntities(ret)
 
     return setmetatable(ret, worldMetaTable)
-
 end
 
 --- Adds an Entity to the world.
 -- Also call this on Entities that have changed Components such that they
 -- match different Filters.
--- @param world
--- @param entity
 function tiny.addEntity(world, entity)
     local e2a = world.entitiesToAdd
     e2a[#e2a + 1] = entity
@@ -394,8 +392,6 @@ end
 tiny_addEntity = tiny.addEntity
 
 --- Adds a System to the world.
--- @param world
--- @param system
 function tiny.addSystem(world, system)
     local s2a = world.systemsToAdd
     s2a[#s2a + 1] = system
@@ -403,10 +399,6 @@ end
 tiny_addSystem = tiny.addSystem
 
 --- Shortcut for adding multiple Entities and Systems to the World.
--- @param world
--- @param ... Systems and Entities
--- @see addEntity
--- @see addSystem
 function tiny.add(world, ...)
     local obj
     for i = 1, select("#", ...) do
@@ -423,8 +415,6 @@ end
 tiny_add = tiny.add
 
 --- Removes an Entity to the World.
--- @param world
--- @param entity
 function tiny.removeEntity(world, entity)
     local e2r = world.entitiesToRemove
     e2r[#e2r + 1] = entity
@@ -432,8 +422,6 @@ end
 tiny_removeEntity = tiny.removeEntity
 
 --- Removes a System from the world.
--- @param world
--- @param system
 function tiny.removeSystem(world, system)
     local s2r = world.systemsToRemove
     s2r[#s2r + 1] = system
@@ -441,10 +429,6 @@ end
 tiny_removeSystem = tiny.removeSystem
 
 --- Shortcut for removing multiple Entities and Systems from the World.
--- @param world
--- @param ... Systems and Entities
--- @see removeEntity
--- @see removeSystem
 function tiny.remove(world, ...)
     local obj
     for i = 1, select("#", ...) do
@@ -462,7 +446,6 @@ tiny_remove = tiny.remove
 
 -- Adds and removes Systems that have been marked from the World.
 function tiny_manageSystems(world)
-
         local s2a, s2r = world.systemsToAdd, world.systemsToRemove
 
         -- Early exit
@@ -495,6 +478,11 @@ function tiny_manageSystems(world)
                 end
             end
             s2r[i] = nil
+
+            -- Clean up System
+            system.world = nil
+            system.entities = nil
+            system.indices = nil
         end
 
         -- Add Systems
@@ -505,8 +493,11 @@ function tiny_manageSystems(world)
                 entityIndices = {}
                 system.entities = entityList
                 system.indices = entityIndices
-                system.active = true
+                if system.active == nil then
+                    system.active = true
+                end
                 system.modified = true
+                system.world = world
                 index = #systems + 1
                 systemIndices[system] = index
                 systems[index] = system
@@ -529,12 +520,10 @@ function tiny_manageSystems(world)
             end
             s2a[i] = nil
         end
-
 end
 
 -- Adds and removes Entities that have been marked.
 function tiny_manageEntities(world)
-
     local e2a, e2r = world.entitiesToAdd, world.entitiesToRemove
 
     -- Early exit
@@ -580,7 +569,6 @@ function tiny_manageEntities(world)
         e2r[i] = nil
     end
 
-
     -- Add Entities
     for i = 1, #e2a do
         entity = e2a[i]
@@ -612,25 +600,24 @@ function tiny_manageEntities(world)
 
     -- Update Entity count
     world.entityCount = entityCount
-
 end
 
---- Updates the World.
+--- Updates the World by dt (delta time). Takes an optional parameter, `filter`,
--- Put this in your main loop.
+-- which is a Filter that selects Systems from the World, and updates only those
--- @param world
+-- Systems. If `filter` is not supplied, all Systems are updated. Put this
--- @param dt Delta time
+-- function in your main loop.
-function tiny.update(world, dt)
+function tiny.update(world, dt, filter)
 
     tiny_manageSystems(world)
     tiny_manageEntities(world)
 
     local systems = world.systems
-    local system, update, onModify, entities
+    local system, update, interval, onModify
 
     --  Iterate through Systems IN ORDER
     for i = 1, #systems do
         system = systems[i]
-        if system.active then
+        if system.active and ((not filter) or filter(world, system)) then
 
             -- Call the modify callback on Systems that have been modified.
             onModify = system.onModify
@@ -641,7 +628,19 @@ function tiny.update(world, dt)
             --Update Systems that have an update method (most Systems)
             update = system.update
             if update then
-                update(system, dt)
+                interval = system.interval
+                if interval then
+                    local bufferedTime = (system.bufferedTime or 0) + dt
+                    while bufferedTime >= interval do
+                        bufferedTime = bufferedTime - interval
+                        if update then
+                            update(system, interval)
+                        end
+                    end
+                    system.bufferedTime = bufferedTime
+                else
+                    update(system, dt)
+                end
             end
 
             system.modified = false
@@ -650,7 +649,6 @@ function tiny.update(world, dt)
 end
 
 --- Removes all Entities from the World.
--- @param world
 function tiny.clearEntities(world)
     for e in pairs(world.entities) do
         tiny_removeEntity(world, e)
@@ -658,7 +656,6 @@ function tiny.clearEntities(world)
 end
 
 --- Removes all Systems from the World.
--- @param world
 function tiny.clearSystems(world)
     local systems = world.systems
     for i = #systems, 1, -1 do
@@ -667,35 +664,24 @@ function tiny.clearSystems(world)
 end
 
 --- Gets number of Entities in the World.
--- @param world
--- @return An integer
 function tiny.getEntityCount(world)
     return world.entityCount
 end
 
 --- Gets number of Systems in World.
--- @param world
--- @return An integer
 function tiny.getSystemCount(world)
     return #(world.systems)
 end
 
 --- Gets the index of a System in the World. Lower indexed Systems are processed
 -- before higher indexed systems.
--- @param world
--- @param system
--- @return An integer between 1 and world:getSystemCount() inclusive
 function tiny.getSystemIndex(world, system)
     return world.systemIndices[system]
 end
 
---- Sets the index of a System in the World. Changes the order in
+--- Sets the index of a System in the World, and returns the old index. Changes
--- which they Systems processed, because lower indexed Systems are processed
+-- the order in which they Systems processed, because lower indexed Systems are
--- first.
+-- processed first.
--- @param world
--- @param system
--- @param index
--- @return Old index
 function tiny.setSystemIndex(world, system, index)
     local systemIndices = world.systemIndices
     local oldIndex = systemIndices[system]