WhatIsNPL

What is NPL?

NPL is short for neural parallel language.

• NPL is an open source collection of libraries based on C/C++ and Lua.
• NPL provides essential functionality for building 3D/2D/Server applications.
• NPL is a single language solution for advanced and interactive GUI, complex opengl/DirectX 3D graphics, scalable webserver and distributed software frameworks. It is cross-platform, high performance, extensible and debuggable.
• NPL is a language system initially designed to operate like the brain. Nodes and connections are ubiquitous; threading and networking logics are hidden from developers.

Facts You Should Know

• NPL runtime is written in C/C++. It can utilize the luajit compiler, which dynamically compiles script/byte code into native machine code, thus it can approach native C/C++ performance with some caveats.
• NPL runtime native API is a rich collection of C/C++ functions that is callable from NPL script. It includes networking, graphics, io, audio, assets management, and core NPL/ParaEngine infrastructure. NPL Reference contains its full documentation. However, 99% of time, we never use native API directly in NPL script.
• Instead, we use NPL libraries, which are pure NPL/lua script files, distributed open sourced or in a zip/pkg file. Over 1 million lines of fully-documented NPL script code are available for use. Try to search in the repository of NPL source code, before writing your own.
• NPL libraries are all written in object oriented fashion, code is organized in folders and table namespaces.
• Because NPL is written in C/C++, it is cross-platform, extensible and easy to integrate with other thirty-party tools. For examples, NPLRuntime is distributed with following built in plugins: bullet(a robust 3d physics engine), mono(C# scripting module with NPL API), mysql/sqlite(database engine), libcurl(a robust http/ssh client).

Hello World in NPL

Run in command line npl helloworld.lua. The content of helloworld.lua is like this:

print("hello world");

Now, there comes a more complicated helloworld. It turns an ordinary helloworld.lua file into a neuron file, by associating an activate function with it. The file is then callable from any NPL thread or remote computer by its NPL address(url).

local function activate()
   if(msg) then
      print(msg.data or "");
   end
   NPL.activate("(gl)helloworld.lua", {data="hello world!"})
end
NPL.this(activate);

Why Should I Use NPL?

You may write your next big project in NPL, if you meet any following condition, if not all:

• If you like truly dynamic language like lua.
• If you care about C/C++ compatibility and performance.
• Coming from the C/C++ world, yet looking for a replacement language for java/C#, that can handle heavy load of 2d/3d graphical client or server applications, easier than C/C++.
• Looking for a scripting language for both client and server development that is small and easy to deploy on windows and other platforms.
• Looking for a dynamic language that can be just-in-time compiled and modified at run time.

Note: calling API between C++/scripting runtime, usually requires a context switch which is computationally expensive most language also involves type translation (such as string parameter), managed/unmanaged environment transition (garbage collection), etc. NPL/LUA has the smallest cost among all languages, and with luajit, type translation is even unnecessary. Thus making it ideal to choose NPL when some part of your responsive app needs to be developed in C/C++.

Background

NPL prototype was designed in 2004, which was then called 'parallel oriented language'. In 2005, it was implemented together with ParaEngine, a distributed 3d computer game engine.

Why a New Programming Language?

NPL is initially designed to write flexible algorithms that works in a multi-threaded, and distributed environment with many computers across the network. More specifically, I want to have a language that is suitable for writing neural network algorithms, 3d simulation and visualization. Lua and C/C++ affinity was chosen from the beginning.

Communicate Like The Brain

Although we are still unclear about our brain's exact computational model, however, following fact seems ubiquitous in our brain.

• The brain consists of neurons and connections.
• Data flows from one neuron to another: it is asynchronously, single-direction and without callback. Communication in NPL is the same as above. Each file can become a neuron file to receive messages from other neuron files. They communicate asynchronously without callback. As a result, no lock is required because there is no shared data; making it both simple and fast to write and test distributed algorithms and deploy software in heterogeneous environment.

References

Click the links, if you like to read the old history:

• NPL prototype doc in 2005
• A thesis on NPL/ParaEngine in 2005
• A book on ParaEngine in 2006