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NLua

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Status
linux Linux
win Build status
mac Build Status
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linuxnet Build Status

Bridge between Lua world and the .NET (compatible with .NET/UWP/Mac/Linux/Android/iOS/tvOS)

Building

msbuild NLua.sln

NLua allows the usage of Lua from C#, on UWP, Windows, Linux, Mac, iOS , Android.

Cmd

NLua is a fork project of LuaInterface (from Fábio Mascarenhas/Craig Presti).

Example: You can use/instantiate any .NET class without any previous registration or annotation.

	public class SomeClass
	{
		public string MyProperty {get; private set;}
		
		public SomeClass (string param1 = "defaulValue")
		{
			MyProperty = param1;
		}
		
		public int Func1 ()
		{
			return 32;
		}
		
		public string AnotherFunc (int val1, string val2)
		{
			return "Some String";
		}
		
		public static string StaticMethod (int param)
		{
			return "Return of Static Method";
		}
        }
  • Using UTF-8 Encoding:

NLua runs on top of KeraLua binding, it encodes the string using the ASCII encoding by default. If you want to use UTF-8 encoding, just set the Lua.State.Encoding property to Encoding.UTF8:

using (Lua lua = new Lua())
{
	lua.State.Encoding = Encoding.UTF8;
	lua.DoString("res = 'Файл'");
	string res = (string)lua["res"];

	Assert.AreEqual("Файл", res);
}

Creating Lua state:

	using NLua;
	
	Lua state = new Lua ()

Evaluating simple expressions:

	var res = state.DoString ("return 10 + 3*(5 + 2)")[0] as double;
	// Lua can return multiple values, for this reason DoString return a array of objects

Passing raw values to the state:

	double val = 12.0;
	state ["x"] = val; // Create a global value 'x' 
	var res = (double)state.DoString ("return 10 + x*(5 + 2)")[0];

Retrieving global values:

	state.DoString ("y = 10 + x*(5 + 2)");
	double y = (double) state ["y"]; // Retrieve the value of y

Retrieving Lua functions:

	state.DoString (@"
	function ScriptFunc (val1, val2)
		if val1 > val2 then
			return val1 + 1
		else
			return val2 - 1
		end
	end
	");
	var scriptFunc = state ["ScriptFunc"] as LuaFunction;
	var res = (int)scriptFunc.Call (3, 5).First ();
	// LuaFunction.Call will also return a array of objects, since a Lua function
	// can return multiple values

##Using the .NET objects.##

Passing .NET objects to the state:

	SomeClass obj = new SomeClass ("Param");
	state ["obj"] = obj; // Create a global value 'obj' of .NET type SomeClass 
	// This could be any .NET object, from BCL or from your assemblies

Using .NET assemblies inside Lua:

To access any .NET assembly to create objects, events etc inside Lua you need to ask NLua to use CLR as a Lua package. To do this just use the method LoadCLRPackage and use the import function inside your Lua script to load the Assembly.

	state.LoadCLRPackage ();
	state.DoString (@" import ('MyAssembly', 'MyNamespace') 
			   import ('System.Web') ");
	// import will load any .NET assembly and they will be available inside the Lua context.

Creating .NET objects: To create object you only need to use the class name with the ().

state.DoString (@"
	 obj2 = SomeClass() -- you can suppress default values.
	 client = WebClient()
	");

Calling instance methods: To call instance methods you need to use the : notation, you can call methods from objects passed to Lua or to objects created inside the Lua context.

	state.DoString (@"
	local res1 = obj:Func1()
	local res2 = obj2:AnotherFunc (10, 'hello')
	local res3 = client:DownloadString('http://nlua.org')
	");

Calling static methods: You can call static methods using only the class name and the . notation from Lua.

	state.DoString (@"
	local res4 = SomeClass.StaticMethod(4)
	");

Calling properties: You can get (or set) any property using . notation from Lua.

	state.DoString (@"
	local res5 = obj.MyProperty
	");

All methods, events or property need to be public available, NLua will fail to call non-public members.

If you are using Xamarin.iOS you need to Preserve the class you want to use inside NLua, otherwise the Linker will remove the class from final binary if the class is not in use.

##Sandboxing##

There is many ways to sandbox scripts inside your application. I strongly recommend you to use plain Lua to do your sandbox. You can re-write the import function before load the user script and if the user try to import a .NET assembly nothing will happen.

	state.DoString (@"
		import = function () end
	");

Lua-Sandbox user-list

Unity Integration

  1. Build for .Net 2.0 or Download KeraLua and NLua from NuGet (use the Download package link)
  2. if Download: change the file extensions from .nupkg to .zip
  3. create folders in your Unity project's Assets directory Plugins/KeraLua and Plugins/NLua
  4. extract the netstandard2.0 contents of those zip files into the newly created unity folders. Your tree should look roughly like this (with KeraLua runtimes customized to your build targets)
Plugins
├── KeraLua
│   ├── LICENSE
│   ├── LICENSE.meta
│   ├── lib
│   │   ├── netstandard2.0
│   │   │   ├── KeraLua.dll
│   │   │   ├── KeraLua.dll.meta
│   │   │   ├── KeraLua.xml
│   │   │   └── KeraLua.xml.meta
│   │   └── netstandard2.0.meta
│   ├── lib.meta
│   ├── runtimes
│   │   ├── linux-x64
│   │   │   ├── native
│   │   │   │   ├── liblua54.so
│   │   │   │   └── liblua54.so.meta
│   │   │   └── native.meta
│   │   ├── linux-x64.meta
│   │   ├── osx
│   │   │   ├── native
│   │   │   │   ├── liblua54.dylib
│   │   │   │   └── liblua54.dylib.meta
│   │   │   └── native.meta
│   │   ├── osx.meta
│   │   ├── win-x64
│   │   │   ├── native
│   │   │   │   ├── lua54.dll
│   │   │   │   └── lua54.dll.meta
│   │   │   └── native.meta
│   │   ├── win-x64.meta
│   │   ├── win-x86
│   │   │   ├── native
│   │   │   │   ├── lua54.dll
│   │   │   │   └── lua54.dll.meta
│   │   │   └── native.meta
│   │   └── win-x86.meta
│   └── runtimes.meta
├── KeraLua.meta
├── NLua
│   ├── LICENSE
│   ├── LICENSE.meta
│   ├── lib
│   │   ├── netstandard2.0
│   │   │   ├── NLua.dll
│   │   │   └── NLua.dll.meta
│   │   └── netstandard2.0.meta
│   └── lib.meta
└── NLua.meta
  1. Go through each KeraLua runtime liblua54 files in the Unity inspector and set the correct Platform settings for both editor and standalone based on the folder. Don't forget to apply

Notes for unity

  • you will likely want to append to package.path you can do it with something like this lua.DoString("package.path = package.path .. \";" + Application.persistentDataPath + "/?/?.lua;" + Application.persistentDataPath + "/?.lua\"");
  • you will want to expose Debug.Log to lua (and override the print function to see lua logs)
  • numbers will come back as double type
  • fields set on the lua instance may be null and you will need to handle it

Copyright (c) 2024 Vinicius Jarina (viniciusjarina@gmail.com)

NLua 1.4.x

NLua huge cleanup and refactor after a few years.

  • Moved to .NET C# style.
  • Using KeraLua as nuget dependencie.
  • Droped support for KopiLua/Silverlight/Windows Phone

NLua 1.3.2

  • Migration to unified Xamarin.iOS (iOS)
  • Added __call method to call Actions/Funcs from Lua as Lua functions.
  • Fixed #116 problem accessing base class method
  • Fixed #117 problem with same method in class and base class
  • Fixed #125 calling methods with params keyword.

NLua 1.3.2

NLua 1.3.0

NLua 1.2.0

NLua 1.1.0

  • Port to WP7 (Thanks to Mangatome)
  • NLua now using Lua 5.2.2
  • Bug fixes.

NLua 1.0.0

  • Forked from LuaInterface 2.0.4
  • Added iOS support using KeraLua (C# P/Invoke Lua)

###Help NLua###

  • Contributing

  • NLua uses the Mono Code-Style http://www.mono-project.com/Coding_Guidelines .
  • Please, do not change the line-end or re-indent the code.
  • Run the tests before you push.
  • Avoid pushing style changes (unless they are really needed), renaming and move code.

Old History

LuaInterface

Copyright (c) 2003-2006 Fabio Mascarenhas de Queiroz

Maintainer: Craig Presti, craig@vastpark.com

lua51.dll and lua51.exe are Copyright (c) 2005 Tecgraf, PUC-Rio

Getting started with NLua:

  • Look at src/TestNLua/TestLua to see an example of usage from C# (optionally you can run this from inside the NLua solution using the debugger).
    Also provides a good example of how to override .NET methods of Lua and usage of NLua from within your .NET application.

  • Look at samples/testluaform.lua to see examples of how to use .NET inside Lua

  • More installation and usage instructions in the doc/guide.pdf file.

What's new in LuaInterface 2.0.3

  • Fix: Private methods accessible via LuaInterface
  • Fix: Method overload lookup failures
  • Fix: Lua DoFile memory leaks when file not found (submitted by Paul Moore)
  • Fix: Lua Dispose not freeing memory (submitted by Paul Moore)
  • Fix: Better support for accessing indexers
  • Fix: Parsing error for MBCS characters (qingrui.li)
  • Fix: Dispose errors originating from LuaTable, LuaFunction, LuaUserData
  • Fix: LuaInterface no longer disposes the state when passed one via the overloaded constructor
  • Added: LoadString and LoadFile (submitted by Paul Moore)
  • Added: Overloaded DoString
  • Added: Lua debugging support (rostermeier)

What's new in LuaInterface 2.0.1

  • Apparently the 2.0 built binaries had an issue for some users, this is just a rebuild with the lua sources pulled into the LuaInterface.zip

What's new in LuaInterface 2.0

  • The base lua5.1.2 library is now built as entirely manged code. LuaInterface is now pure CIL
  • Various adapters to connect the older x86 version of lua are no longer needed
  • Performance fixes contributed by Toby Lawrence, Oliver Nemoz and Craig Presti

What's new in LuaInterface 1.5.3

  • Internal lua panics (due to API violations) now throw LuaExceptions into .net
  • If .net code throws an exception into Lua and lua does not handle it, the original exception is forwarded back out to .net land.
  • Fix bug in the Lua 5.1.1 gmatch C code - it was improperly assuming gmatch only works with tables.

What's new in LuaInterface 1.5.2

  • Overriding C# methods from Lua is fixed (broken with .net 2.0!)
  • Registering static C# functions for Lua is fixed (broken with Lua-5.1.1)
  • Rebuilt to fix linking problems with the binaries included in 1.5.1
  • RegisterFunction has been leaking things onto the stack

What's new in LuaInterface 1.5.1

Fix a serious bug w.r.t. garbage collection - made especially apparent with the new lua5.1 switch: If you were very unlucky with timing sometimes Lua would loose track of pointers to CLR functions.

When I added support for static methods, I allowed the user to use either a colon or a dot to separate the method from the class name. This was not correct - it broke disambiguation between overloaded static methods.
Therefore, LuaInterface is now more strict: If you want to call a static method, you must use dot to separate the method name from the class name. Of course you can still use a colon if an instance is being used.

Static method calls are now much faster (due to better caching).

What's new in LuaInterface 1.5

LuaInterface is now updated to be based on Lua5.1.1. You can either use your own build/binaries for Lua5.1.1 or use the version distributed here. (Lots of thanks to Steffen Itterheim for this work!)

LuaInterface.Lua no longer has OpenLibs etc... The base mechanism for library loading for Lua has changed, and we haven't yet broken apart the library loading for LuaInterface. Instead, all standard Lua libraries are automatically loaded at start up.

Fixed a bug where calls of some static methods would reference an invalid pointer.

Fixed a bug when strings with embedded null characters are passed in or out of Lua (Thanks to Daniel N�ri for the report & fix!)

The native components in LuaInterface (i.e. Lua51 and the loader) are both built as release builds - to prevent problems loading standard windows libraries.

Note: You do not need to download/build lua-5.1.1.zip unless you want to modify Lua internals (a built version of lua51.dll is included in the regular LuaInterface distribution)

What's New in LuaInterface 1.4

Note: Fabio area of interest has moved off in other directions (hopefully only temporarily). I've talked with Fabio and he's said he's okay with me doing a new release with various fixes I've made over the last few months. Changes since 1.3:

Visual Studio 2005/.Net 2.0 is supported.

Compat-5.1 is modified to expect backslash as the path seperator.

LuaInterface will now work correctly with Generic C# classes.

CLR inner types are now supported.

Fixed a problem where sometimes Lua proxy objects would be associated with the wrong CLR object.

If a CLR class has an array accessor, the elements can be accessed using the regular Lua indexing interface.

Add CLRPackage.lua to the samples directory. This class makes it much easier to automatically load referenced assemblies. In the next release this loading will be automatic.

To see an quick demonstration of LuaInterface, cd into nlua/samples and then type: ....\Built\debug\LuaRunner.exe testluaform.lua

Various other minor fixes that I've forgotten. I'll keep better track next time.

Note: LuaInterface is still based on Lua 5.0.2. If someone really wants us to upgrade to Lua 5.1 please send me a note. In the mean time, I'm also distributing a version of Lua 5.0.2 with an appropriate VS 2005 project file. You do not need to download this file unless you want to modify Lua internals (a built version of lua50.dll is included in the regular LuaInterface distribution)

What's New in LuaInterface 1.3

LuaInterface now works with LuaBinaries Release 2 (http://luabinaries.luaforge.net) and Compat-5.1 Release 3 (http://luaforge.net/projects/compat). The loader DLL is now called luanet.dll, and does not need a nlua.lua file anymore (just put LuaInterface.dll in the GAC, luanet.dll in your package.cpath, and do require"luanet").

Fixed a bug in the treatment of the char type (thanks to Ron Scott).

LuaInterface.dll now has a strong name, and can be put in the GAC (thanks to Ivan Voras).

You can now use foreach with instances of LuaTable (thanks to Zachary Landau).

There is an alternate form of loading assemblies and importing types (based on an anonymous contribution in the Lua wiki). Check the _alt files in the samples folder.

What's New in LuaInterface 1.2.1

Now checks if two LuaInterface.Lua instances are trying to share the same Lua state, and throws an exception if this is the case. Also included readonly clauses in public members of the Lua and ObjectTranslator classes.

This version includes the source of LuaInterfaceLoader.dll, with VS.Net 2003 project files.

What's New in LuaInterface 1.2

LuaInterface now can be loaded as a module, so you can use the lua standalone interpreter to run scripts. Thanks to Paul Winwood for this idea and sample code showing how to load the CLR from a C++ program. The module is "nlua". Make sure Lua can find nlua.lua, and LuaInterfaceLoader.dll is either in the current directory or the GAC. The samples now load LuaInterface as a module, in its own namespace.

The get_method_bysig, get_constructor_bysig and make_object were changed: now you pass the names of the types to them, instead of the types themselves. E.g:

get_method_bysig(obj,"method","System.String")

instead of

String = import_type("System.String") get_method_bysig(obj,"method",String)

Make sure the assemblies of the types you are passing have been loaded, or the call will fail. The test cases in src/TestLuaInterface/TestLua.cs have examples of the new functions.