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/*! \page bindings Bindings

\htmlinclude .bindings.doc.toc

\section bindings_start Available bindings

\subsection bindings_binding_lua Lua Binding
Most of Simgrid modules require a  good level in C programming, since simgrid is used to be as standard C library.
 Sometime users prefer using some kind of « easy scripts » or a language easier to code with, for their works,
 which avoid dealing with C errors, and sometime an important  gain of time.
Besides Java Binding, Lua  and Ruby bindings are available since version 3.4 of Simgrid
for MSG Module, and we are currenlty working on bindings for other modules.


\subsubsection bindings_binding_lua_about What is lua ?
Lua is a lightweight, reflective, imperative and functional programming language,
 designed as a scripting language with extensible semantics as a primary goal (see official web site <a href="http://www.lua.org">here</a>).
\subsubsection bindings_binding_lua_why Why lua ?
Lua is a fast, portable and powerful script language, quite simple to use for developpers.
it combines procedural features with powerful data description facilities,
 by using a simple, yet powerful, mechanism of tables.
Lua has a relatively simple C API compared to other scripting languages,
and accordingly it provides a robust, easy to use it.
\subsubsection bindings_binding_lua_simgrid How to use lua in Simgrid ?
Actually, the use of lua in Simgrid is quite simple, you have just to follow the same steps as coding with C in Simgird :
  - Coding functions coresponding to each process
  - loading the platforme/deployment XML file that describe the environment of simulation
  - and … Running the Simulation.
  
\dontinclude lua/masterslave/master.lua
\subsubsection bindings_binding_lua_example_master_slave Master/Slave Example

 \li Master Code
 \until end_of_master
we mainly  use   simgrid.Task.new(task_name,computation_size,communication_size) to create our MSG Task, 
         then simgrid.Task.send(task,alias) to send it.
we use also simgrid.Task.name(task), to get the task's name. 

\dontinclude lua/masterslave/slave.lua
\li Slave Code
\until end_of_slave
Here, we see the use of simgrid.Task.recv(alias) to receive a task with a specific alias,
this function return directly the task recevied.

\dontinclude lua/masterslave/master_slave.lua
\li Set Environmenet and run application
\until simgrid.clean()

\subsubsection bindings_binding_lua_example_data Exchanging Data
You can also exchange data between Process using lua. for that, you have to deal with lua task as a table,
since lua is based itself on a mechanism of tables,
so you can exchange any kind of data (tables, matrix, strings,…) between process via tasks.

\li Sender process
\verbatim 
  task = simgrid.Task.new("data_task",task_comp,task_comm);
  task['matrix'] = my_matrix;
  task['table'] = my_table;
  task['message'] = "Hello from (Lua || Simgrid ) !! "
  …
  simgrid.Task.send(task,alias)
\endverbatim
        After creating task, we associate to it various kind of data with a specific key (string in this case)
        to distinguish between data variables. The receiver will use this key to access easily to datas.


\li Receiver processe
\verbatim
  task = simgrid.Task.recv(alias);
  sender_matrix = task['matrix'];
  sender_table = task['table'];
  sender_message = task['message']
  ...
\endverbatim
        Note that in lua, both sender and receiver share the same lua task.
        So that the receiver could joint data directly on the received task without sending it back.
        You can find  a complet example (matrix multiplication case) in the file example/lua/mult_matrix.lua. 


\subsubsection bindings_binding_lua_example_bypass Bypass XML
        maybe you wonder if there is a way to bypass the XML files,
         and describe your platform directly from the code, with lua bindings it's Possible !! how ?
        We provide some additional (tricky?) functions in lua that allows you to set up your own platform without using the XML files
     ( this can be useful for large platforms, so a simple for loop will avoid you to deal with an annoying XML File ;) )
     

\li set Routing mode
\verbatim
   simgrid.AS.new{id="AS0",mode="Full"};
\endverbatim

\li set Hosts
\verbatim
  simgrid.Host.new{id="Tremblay",power=98095000};
  simgrid.Host.new{id="Jupiter",power=76296000};
  simgrid.Host.new{id="Fafard",power=76296000};
  simgrid.Host.new{id="Ginette",power=48492000};
  simgrid.Host.new{id="Bourassa",power=48492000};
\endverbatim
  we use simgrid.Host.new{id=id_host,power=power_host} to instanciate our hosts.

\li set Links
\verbatim
  for i=0,11 do
    simgrid.Link.new{id=i,bandwidth=252750+ i*768,latency=0.000270544+i*0.087};    --  some crazy values ;)
  end
\endverbatim
  we used simgrid.Link.new{id=link_id,bandwidth=bw,latency=lat} with a simple for loop to create all links we need (much easier than XML hein ?)

\li set Routes
\verbatim
-- simgrid.Route.new(src_id,des_id,links_nb,links_list)
   simgrid.Route.new("Tremblay","Jupiter",1,{"1"});
   simgrid.Route.new("Tremblay","Fafard",6,{"0","1","2","3","4","8"});
   simgrid.Route.new("Tremblay","Ginette",3,{"3","4","5"});
   simgrid.Route.new("Tremblay","Bourassa",7,{"0","1","3","2","4","6","7"});

   simgrid.Route.new("Jupiter","Tremblay",1,{"1"});
   simgrid.Route.new("Jupiter","Fafard",7,{"0","1","2","3","4","8","9"});
   simgrid.Route.new("Jupiter","Ginette",4,{"3","4","5","9"});
   simgrid.Route.new("Jupiter","Bourassa",8,{"0","1","2","3","4","6","7","9"});
   ...
\endverbatim
  for each host you have to specify which route to choose to access to the rest of hosts connected in the grid.
  
\li Save platform
\verbatim
  simgrid.register_platform();
\endverbatim
Don't forget to register your platform, that SURF callbacks starts their work ;)

\li set application
\verbatim
   simgrid.Host.setFunction("Tremblay","Master",4,{"20","550000000","1000000","4"});
   simgrid.Host.setFunction("Bourassa","Slave",1,{"0"});
   simgrid.Host.setFunction("Jupiter","Slave",1,{"1"});
   simgrid.Host.setFunction("Fafard","Slave",1,{"2"});
   simgrid.Host.setFunction("Ginette","Slave",1,{"3"});
\endverbatim
  you don't  need to use a deployment XML file, thanks to  simgrid.Host.setFunction(host_id,function,args_number,args_list) 
  you can associate functions for each host with arguments if needed .

\li
\verbatim
   simgrid.register_application();
\endverbatim
Yes, Here too you have to resgiter your application before running the simulation.

the full example is distributed in the file examples/lua/master_slave_bypass.lua

\subsection bindings_binding_ruby Ruby Binding


\subsubsection bindings_binding_ruby_simgrid Use Ruby in Simgrid
Since v3.4, the use of <a href="http://ruby-lang.org">ruby</a> in simgrid is available for the MSG Module.
you can find almost all MSG functionalities in Ruby code, that allows you to set up your environment, manage tasks between hosts and run the simulation.

\subsubsection bindings_binding_ruby_example Master/Slave Ruby Application
for each process method(master and slave in this example), you have to associate a ruby class, that should inherit from <i>MSG::Process</i> ruby class,
  with a 'main' function that describe the behaviour of the process during the simulation.
\li required stuff
\verbatim
require 'simgrid'
include MSG
\endverbatim

\li Master code
\verbatim
class Master < MSG::Process 
  # main : that function that will be executed when running simulation

  def main(args) # args is an array containing arguments for function master
   size = args.size
   for i in 0..size-1
     MSG::info("args["+String(i)+"]="+args[i])
   end
  
   raise "Master needs 3 arguments" if size < 3 
   numberOfTask = Integer(args[0]) 
   taskComputeSize = Float(args[1])
   taskCommunicationSize = Float(args[2])
   slaveCount = Integer(args[3]) 
   
   # Creates and sends the tasks
    for i in 0..numberOfTask-1
     task = Task.new("Task_"+ i.to_s, taskComputeSize , taskCommunicationSize);
     mailbox = "slave " + (i%slaveCount).to_s
     MSG::info("Master Sending "+ task.name + " to " + mailbox + " with Comput Size " + 
           task.compSize.to_s)
     task.send(mailbox)
     MSG::info("Master Done Sending " + task.name + " to " + mailbox)
    end
  
   # Sending Finalize MSG::Tasks
   MSG::info("Master: All tasks have been dispatched. Let's tell everybody the computation is over.")
   for i in 0..slaveCount-1
     mailbox = "slave " + i.to_s
     finalize_task = Task.new("finalize",0,0)
     finalize_task.send(mailbox)
   end
   MSG::info("Master : Everything's Done")
  end    
end
\endverbatim


the class MSG::Task contains methods that allows the management of the native MSG tasks.
in master ruby code we used : 
  - <i>MSG::Task.new(task_name,compute_size,communication_size)</i> : to instanciate a new task.
  - <i>MSG::Task.send(mailbox)</i> : to send the task via a mailbox alias.
  - <i>MSG::Task.name</i> : to get the task's name.

\li Slave code
\verbatim
class Slave < MSG::Process

  def main(args)
    mailbox = "slave " + args[0]
    for i in 0..args.size-1
      MSG::debug("args["+String(i)+"]="+args[i])
    end

    while true
       MSG::info("Slave '"+ mailbox +"' waiting for new task");
       task = Task.receive(mailbox)
       if (task.name == "finalize")
               break
       end
       task.execute
       MSG::info("Slave '" + mailbox + "' done executing task "+ task.name + ".")
    end
    MSG::info("I'm done, see you")
  end
end
\enverbatim
to receive a task, we use the method <i>MSG::Task.receive(mailbox)</i> that return a MSG:Task object (received task).

\li Main chunk

\verbatim
require 'simgrid'
include MSG
(...)

if (ARGV.length == 2) 
        MSG.createEnvironment(ARGV[0])
        MSG.deployApplication(ARGV[1])

else

        MSG.createEnvironment("platform.xml")
        MSG.deployApplication("deploy.xml")
end
MSG.run
puts "Simulation time : " + MSG.getClock.to_s
MSG.exit
\endverbatim

- <i>MSG.createEnvironment(platform_file)</i> : set up the environment
- <i>MSG.deployApplication(deployment_file)</i> : load the deployment file description.
- <i>MSG.run</i> : run the simulation

\subsubsection bindings_binding_ruby_data Exchanging data 
ruby bindings provides two ways to exchange data between ruby processes.
\li MSG::Task.join & MSG::Task.data <br/>

  the MSG::Task class contains 2 methods that allows a data exchange between 2 process.
  
  -<i>MSG::Task.join</i> : makes possible to join any kind of ruby data within a task.
  \verbatim
   ...
   myTable = Array.new
   myTable <<1<<-2<<45<<67<<87<<76<<89<<56<<78<<3<<-4<<99
   # Creates and send Task With the Table inside
   task = MSG::Task.new("quicksort_task",taskComputeSize, taskCommunicationSize);
   task.join(myTable);
   ...
   task.send(mailbox);
   \endverbatim
   -<i>MSG::Task.data</i> : to access to the data contained into the task.
   \verbatim
   ...
   task = MSG::Task.receive(recv_mailbox.to_s)
   table = task.data
   quicksort(table,0,table.size-1)
   ...
   \endverbatim
you can find a complet example illustrating the use of those methods  in file /example/ruby/Quicksort.rb

\li inheritence 
 
 another 'object-oriented' way to do it, is to make your own 'task' class that inherit from  MSG::Task ,
 and contains data you want to deal with, the only 'tricky' thing is that "the initializer" method has no effect ! 
 
 the use of some getter/setter methods would be the simple way to manage your data :)
 \verbatim
class PingPongTask < MSG::Task
  # The initialize method has no effect 
  @time 
  def setTime(t)
    @time = t
  end
  def getTime()
    return @time
  end
end
 \endverbatim
 you can find an example of use in file example/ruby/PingPong.rb

 */