alter-cash / lape

Scripting engine with Pascal-like syntax for FPC and Delphi

Lape

Lape is a scripting engine with a Pascal derived syntax for Free Pascal and Delphi. It's written with speed and a broad platform compatibility in mind. The syntax is backwards compatible with Pascal Script (to a certain degree).

Lape is:

• A scripting engine
• A Pascal derived language
  • Basetypes: Integer, Float, Char, String, Boolean, Variant, Array, Record, Union, Enum, Set, Pointer, Function pointer
  • Operations: := = <> > >= < <= @ ^ + - * / ** AND OR DIV XOR NOT IN SHL SHR MOD
  • Constructs: If For Case Repeat While Try Label
  • Optional C style operators: += /= *= -=
  • Internal and external functions (with support for default params & type methods)
  • Internal/external variables and constants (every variable is represented exactly as how it would be by FPC/Delphi)
  • Function directives: override, overload, static, deprecated, experimental, unimplemented
  • Support for local (nested) declarations. So function can have their own constants/types/variables/functions.
  • Operator overloading
  • Multiline strings using double quotes "
  • Optional array "helpers" such as array.SetLength(5), array.Pop() and many more
• Portable
  • Fully written in FPC/Delphi. No need for external libraries.
  • Tested with Linux(x64/aarch64), Windows(x86/x64) and Mac OS(x64/aarch64), but supports virtually every platform FPC supports.
• Extensible
  • New types can easily be added with specified behaviour for operations.
  • Optional foreign function interface which allows native calling of Lape functions and importing of functions without creating wrappers.
• Fast

---

Simple example of running a script:

• Remember to add unit & include search paths to the lape directory

uses
  Classes, Sysutils, lpparser, lpcompiler, lpinterpreter;   

const
  MyScript = 'function DiceRoll: Int32;'           + LineEnding +
             'begin'                               + LineEnding +
             '  Result := Random(1, 6);'           + LineEnding +
             'end;'                                + LineEnding +
             ''                                    + LineEnding +
             'begin'                               + LineEnding +
             '  WriteLn("Rolled a ", DiceRoll());' + LineEnding +
             'end.';

var
  Compiler: TLapeCompiler;
begin
  Randomize();

  Compiler := TLapeCompiler.Create(TLapeTokenizerString.Create(MyScript));
  try
    if Compiler.Compile() then
      RunCode(Compiler.Emitter);
  except
    on E: Exception do
      WriteLn(E.ToString());
  end;
  Compiler.Free();

  ReadLn;
end.