did not make the initial commit correctly. Oh, well. On this commit update, reset and after are implemented and passing tests. Only every is missing

BSD-LICENSE.txt

@@ -0,0 +1,26 @@
+Copyright (c) 2011, Enrique García Cota
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without modification, 
+are permitted provided that the following conditions are met:
+
+  1. Redistributions of source code must retain the above copyright notice, 
+     this list of conditions and the following disclaimer.
+  2. Redistributions in binary form must reproduce the above copyright notice, 
+     this list of conditions and the following disclaimer in the documentation 
+     and/or other materials provided with the distribution.
+  3. Neither the name of MiddleClass nor the names of its contributors 
+     may be used to endorse or promote products derived from this software 
+     without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+OF THE POSSIBILITY OF SUCH DAMAGE.
+

README.textile

@@ -0,0 +1,40 @@
+h1. cron.lua
+
+@cron.lua@ are a set of functions for executing actions at a certain time interval.
+
+h1. Examples of use
+
+* @cron.after(time, f)@ will execute f after the given amount of time units.
+* @cron.every(time, f)@ will repeat the same action periodically.
+* @cron.cancel(id)@ will stop a timed event from happening. @id@ is returned by @cron.after@ and @cron.every@ respectively. It will stop a timed event from happening, or stop a periodic action.
+* @cron.reset()@ removes all timed and periodic actions, and resets the time passed back to 0.
+* @cron.update(dt)@ is needed to be executed on the main program loop. @dt@ is the amount of time that has passed since the last iteration. When @cron.update@ is executed, cron will check the list of pending actions and execute them if needed.
+
+
+h1. Gotchas / Warnings
+
+* @cron.lua@ does *not* implement any hardware or software clock; you will have to provide it with the access to the hardware timers, in the form of periodic calls to @cron.update@
+* @cron@ does not have any defined time units (seconds, milliseconds, etc). You define the units it uses by passing it a @dt@ on @cron.update@. If @dt@ is in seconds, then @cron@ will work in seconds. If @dt@ is in milliseconds, then @cron@ will work in milliseconds.
+
+h1. Installation
+
+Just copy the cron.lua file somewhere in your projects (maybe inside a /lib/ folder) and require it accordingly.
+
+Remember to store the value returned by require somewhere! (I suggest a local variable named @cron@)
+
+<pre>
+local cron = require 'cron'
+</pre>
+
+Also, make sure to read the license file; the text of that license file must appear somewhere in your projects' files.
+
+h1. Specs
+
+This project uses "telescope":https://github.com/norman/telescope for its specs. If you want to run the specs, you will have to install telescope first. Then just enter the spec folder and execute run.lua:
+
+<pre>
+cd path/to/cron.lua/specs
+lua run.lua
+</pre>
+
+

cron.lua

@@ -0,0 +1,60 @@
+-----------------------------------------------------------------------------------------------------------------------
+-- cron.lua - v1.0 (2011-04)
+-- Enrique García Cota - enrique.garcia.cota [AT] gmail [DOT] com
+-- time-related functions for Lua.
+-- inspired by Javascript's setTimeout and setInterval
+-----------------------------------------------------------------------------------------------------------------------
+
+
+local entries = {}
+
+local TimedEntry = {}
+
+function TimedEntry:new(time, callback, ...)
+  return setmetatable( {
+      time = time,
+      callback = callback,
+      args = {...},
+      running = 0
+    },
+    { __index = TimedEntry }
+  )
+end
+
+function TimedEntry:update(dt)
+  self.running = self.running + dt
+  if self.running >= self.time then
+    self.callback(unpack(self.args))
+    self.expired = true
+  end
+end
+
+local cron = {}
+
+function cron.reset()
+  entries = {}
+end
+
+function cron.after(time, callback, ...)
+  assert(type(time) == "number" and time > 0, "time must be a positive number")
+  assert(type(callback) == "function", "callback must be a function")
+
+  local entry = TimedEntry:new(time, callback, ...)
+  entries[entry] = entry
+end
+
+function cron.update(dt)
+  assert(type(dt) == "number" and dt > 0, "dt must be a positive number")
+
+  local expired = {}
+
+  for _, entry in pairs(entries) do
+    entry:update(dt, runningTime)
+    if entry.expired then expired[entry] = entry end
+  end
+
+  for _, entry in pairs(expired) do entries[entry] = nil end
+end
+
+return cron
+

spec/cron_spec.lua

@@ -2,4 +2,65 @@ local cron = require 'cron'
 
 context( 'cron', function()
 
+  local counter = 0
+  local function count(amount)
+    amount = amount or 1
+    counter = counter + amount
+  end
+
+  before(function()
+    counter = 0
+    cron.reset()
+  end)
+
+  context('update', function()
+    test( 'Should throw an error if dt is not a positive number', function()
+      assert_error(function() cron.update() end)
+      assert_error(function() cron.update(-1) end)
+      assert_not_error(function() cron.update(1) end)
+    end)
+  end)
+
+  context('reset', function()
+    test('Should cancel all actions', function()
+      cron.after(1, count)
+      cron.after(2, count)
+      cron.update(1)
+      assert_equal(counter, 1)
+      cron.reset()
+      cron.update(1)
+      assert_equal(counter, 1)
+    end)
+  end)
+
+  context( 'after', function()
+    test( 'Should throw error if time is not a positive number, or f is not function', function()
+      assert_error(function() cron.after('error', count) end)
+      assert_error(function() cron.after(2, 'error') end)
+      assert_error(function() cron.after(-2, count) end)
+      assert_not_error(function() cron.after(2, count) end)
+    end)
+    
+    test( 'Should execute timed actions are executed only once, at the right time', function()
+      cron.after(2, count)
+      cron.after(4, count)
+      cron.update(1)
+      assert_equal(counter, 0)
+      cron.update(1)
+      assert_equal(counter, 1)
+      cron.update(1)
+      assert_equal(counter, 1)
+      cron.update(1)
+      assert_equal(counter, 2)
+    end)
+
+    test( 'Should pass on parameters to the function, if specified', function()
+      cron.after(1, count, 2)
+      cron.update(1)
+      assert_equal(counter, 2)
+    end)
+  end)
+
+
+
 end)