Lua 5.1 for Delphi 2010

Monday, September 28th, 2009 | Delphi 2009, Delphi 2010, Delphi Programming, Lua

This is a Lua 5.1 Wrapper for Delphi 2009 and Delphi 2010 which automatically creates OOP callback functions.

“Lua is a powerful, fast, lightweight, embeddable scripting language, it has been used in many industrial applications (e.g., Adobe’s Photoshop Lightroom), with an emphasis on embedded systems (e.g., the Ginga middleware for digital TV in Brazil) and games (e.g., World of Warcraft). Lua is currently the leading scripting language in games and it has a deserved reputation for performance. To claim to be “as fast as Lua” is an aspiration of other scripting languages.”

This Lua Wrapper is based on Lua-Pascal v0.2 by Marco Antonio Abreu
- converted PChar to PAnsiChar
- converted Char to AnsiChar
- added function LuaLibLoaded: Boolean;
- added a new base class (TLua) with OOP call back functions

Download
LuaDelphi2010-v1.3

History
1.3 Improved Callback, now uses pointer instead of object index. Modified RegisterFunctions to allow methods from other class to be registered, moved object table into TLua class
1.2  Added example on how to extend lua with a delphi dll
1.1  Improved global object table, optimized delphi function calls
1.0  Initial Release

Example
TLua automatically creates OOP callback functions for Delphi <-> Lua:

uses
  Lua, LuaLib;
 
type
  TMyLua = class(TLua)
  published
    function HelloWorld(LuaState: TLuaState): Integer;
  end;
 
function TMyLua.HelloWorld: Integer;
var
  ArgCount: Integer;
  I: integer;
begin
  writeln('Delphi: Hello World');
 
  ArgCount := Lua_GetTop(LuaState);
  writeln('Arguments: ', ArgCount);
  for I := 1 to ArgCount do
    writeln('Arg1', I, ': ', Lua_ToInteger(LuaState, I));
 
  // Clear stack
  Lua_Pop(LuaState, Lua_GetTop(LuaState));
 
  // Push return values
  Lua_PushInteger(LuaState, 101);
  Lua_PushInteger(LuaState, 102);
  Result := 2;
end;
 
var
  MyLua: TLua;
 
begin
  MyLua := TMyLua.Create;
  MyLua.DoFile('Helloworld.lua');
  MyLua.Free;
end;

helloworld.lua

print("LuaDelphi Test");
p1,p2 = HelloWorld(1,2,3)
print "Results:";
print (p1);
print (p2);

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8 Comments to Lua 5.1 for Delphi 2010

Jolyon Smith
September 28, 2009

You might like to link to the Lua site so that people unfamiliar with Lua (as I was) can find out what it is.

http://www.lua.org/home.html

Dennis Spreen
September 28, 2009

Sure. Thanks for that hint!

FrancisR
September 28, 2009

Nothing in the download link

Dennis Spreen
September 29, 2009

Fixed. Download is working now, sorry.

Tony Danby
December 24, 2009

Tried this, good work, works nice ( had to recompile for D6 ). By the way, LUA has all of these IO,Math,OS etc.. libraries and it seems that I cannot use them in my lua scripts for this wrapper.

I have tried adding luaopen_io(LuaInstance );
under your luaopen_base(LuaInstance); line in the constructor, but to no avail.

Any ideas?

Dennis Spreen
December 25, 2009

luaL_openlibs(LuaInstance);

should load all libs

Gerhard Zintel
February 24, 2010

I can not compile this under Linux using Free pascal in Delphi mode. First error:
> fpc -Mdelphi LuaTest.dpr
LuaLib.pas(522,1) Fatal: Syntax error, “identifier” expected but “;” found
could easily be fixed by shifting the last comma from line 518 in front of line 520.

but than I have no idea how to fix the following errors:
Compiling ../Lib/LuaLib.pas
LuaLib.pas(283,3) Warning: cdecl’ared functions have no high parameter
LuaLib.pas(394,3) Warning: cdecl’ared functions have no high parameter
LuaLib.pas(397,3) Warning: cdecl’ared functions have no high parameter
LuaLib.pas(539,27) Error: Identifier not found “GetProcAddress”
LuaLib.pas(574,28) Error: Identifier not found “LoadLibrary”
LuaLib.pas(839,17) Error: Identifier not found “FreeLibrary”
LuaLib.pas(1146) Fatal: There were 3 errors compiling module, stopping

Any help is truly appreciated
Gerhard

Gerhard Zintel
February 24, 2010

To answer partly my own question:
To be compatible with Delphi/Windows I have to use the unit dynlibs that offers the missing functions.

Now your test program compiles with warnings but I get an access violation:
> ./LuaTest
EAccessViolation: Access violation

Program seems not to load the shared library im line 547 of LuaLib.pas

regards
Gerhard

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