miniLua - Lua for Pascal

miniLua is a Pascal binding for Lua 5.5, providing both low-level API access via LuaAPI.pas and high-level object-oriented wrappers via LuaClasses.pas. This package is compatible with both FreePascal (FPC) and Delphi.

Features

• Support for Lua 5.5
• Works with FreePascal (Lazarus) and Delphi
• Low-level API wrapper (LuaAPI.pas) - Direct bindings to Lua C API
• High-level OOP wrapper (LuaClasses.pas) - Easy to use classes and helpers for embedding Lua
• Cross-platform support (Windows, Linux, macOS depending on Lua libraries)
• Simple and clean interface

Installation

For Lazarus (FPC)

1. Open minilua.lpk in Lazarus
2. Compile and install the package
3. Add the package to your project

For Delphi

1. Open minilua.dpk in Delphi
2. Compile and install the package
3. Add the package to your project

Manual Compilation

Add LuaAPI.pas and LuaClasses.pas to your project directly.

Usage

Basic Example - Running Lua Scripts

Here's a simple example of how to initialize Lua and execute a script:

uses
  SysUtils, LuaAPI, LuaClasses;

var
  Lua: TLua;
  Output: string;
begin
  Lua.Init; // Initialize Lua (SafeMode enabled by default)
  try
    // Execute a simple Lua script
    if Lua.State.RunString('return "Hello from Lua!"', Output) then
      WriteLn(Output)
    else
      WriteLn('Error running script');
  finally
    Lua.Close;
  end;
end.

Registering Pascal Functions with Lua

You can expose Pascal functions to Lua scripts:

uses
  SysUtils, LuaAPI, LuaClasses;

function AddNumbers(L: Plua_State): Integer; cdecl;
begin
  // Get arguments from Lua stack (arg1, arg2)
  Result := 1; // Return 1 value
  L.PushInteger(L.ToInteger(1) + L.ToInteger(2));
end;

var
  Lua: TLua;
  Output: string;
begin
  Lua.Init;
  try
    // Register the function as 'add' in Lua
    Lua.State.RegisterGlobal('add', @AddNumbers);
    
    // Call it from Lua
    if Lua.State.RunString('local result = add(5, 3); return result', Output) then
      WriteLn('5 + 3 = ' + Output)
    else
      WriteLn('Error');
  finally
    Lua.Close;
  end;
end.

Exposing Pascal Objects to Lua

Using TLuaObject, you can easily expose object methods to Lua:

uses
  SysUtils, Classes, LuaAPI, LuaClasses;

type
  TCalculator = class(TLuaObject)
  public
    function Multiply(L: Plua_State): Integer; cdecl;
  end;

function TCalculator.Multiply(L: Plua_State): Integer; cdecl;
begin
  Result := 1;
  L.PushNumber(L.ToNumber(1) * L.ToNumber(2));
end;

var
  Lua: TLua;
  Calc: TCalculator;
  Output: string;
begin
  Lua.Init;
  try
    Calc := TCalculator.Create;
    try
      // Register object methods in a Lua table
      Lua.State.Register('calc', Calc);
      // Register specific method
      Lua.State.Register('calc', 'multiply', Calc, @TCalculator.Multiply);
      
      // Use from Lua
      if Lua.State.RunString('return calc.multiply(6, 7)', Output) then
        WriteLn('6 * 7 = ' + Output)
      else
        WriteLn('Error');
    finally
      Calc.Free;
    end;
  finally
    Lua.Close;
  end;
end.

Working with Lua Values

The TLuaHelper record helper provides convenient methods to work with the Lua stack:

var
  L: Plua_State;
begin
  // Push values
  L.PushString('Hello');
  L.PushInteger(42);
  L.PushNumber(3.14);
  L.PushBoolean(True);
  L.PushNil;
  
  // Check types
  if L.IsString(1) then
    WriteLn(L.ToString(1));
  if L.IsInteger(2) then
    WriteLn(IntToStr(L.ToInteger(2)));
  if L.IsNumber(3) then
    WriteLn(FloatToStr(L.ToNumber(3)));
  if L.IsBoolean(4) then
    WriteLn(BoolToStr(L.ToBoolean(4)));
  
  // Pop values
  L.Pop(5);
end;

Project Structure

• LuaAPI.pas - Low-level Lua 5.5 C API bindings (lua.h, lauxlib.h, lualib.h)
• LuaClasses.pas - High-level object-oriented interface for embedding Lua in Pascal applications
• minilua.pas - Package unit (for package compilation)
• minilua.lpk - Lazarus package file
• minilua.dpk / minilua.dproj - Delphi package files
• lib/ - Lua library files
• demos/ - Demo applications for Delphi and Lazarus

Requirements

• FreePascal 3.0+ or Delphi (2009+ recommended for Unicode support)
• Lua shared library (lua55.dll, liblua55.so, liblua55.dylib, pluto.dll, pluto.so) or static library

Documentation

For more information about Lua scripting, visit Lua 5.5 Manual.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Credits

• Original C headers and Lua libraries: TeCGraf / Lua.org
• Original Pascal translation: Lavergne Thomas
• Updates: Bram Kuijvenhoven, Egor Skriptunoff, Vladimir Klimov, Malcome@Japan, Zaher Dirkey