Fallout 2 SSL Compiler (sslc)

A native Delphi/Object Pascal implementation of a Fallout 2 SSL script compiler that produces binary-compatible .int files.

Features

• Complete SSL Parser - Handles all Fallout 2 scripting syntax
• Lexer/Tokenizer - Full lexical analysis with error reporting
• AST Generation - Clean Abstract Syntax Tree architecture
• Bytecode Generator - Produces Fallout 2 virtual machine opcodes
• INT File Writer - Creates binary-compatible .int files
• Built-in Function Database - Supports 100+ Fallout 2 script functions
• Preprocessor - Supports #include, #define, #ifdef/#ifndef/#else/#endif
• CLI Compiler - Command-line interface (sslc.exe)
• VCL GUI - Optional Windows GUI frontend

Supported Syntax

procedure start begin
  display_msg("Hello Wasteland");
end

if (local_var(0) == 1) then begin
  give_exp_points(100);
end

while (counter < 10) do begin
  counter := counter + 1;
end

switch (flag_value) begin
  case 1: display_msg("Case 1"); break;
  case 2: display_msg("Case 2"); break;
  default: display_msg("Default");
end

Preprocessor Directives

The compiler supports C-style preprocessor directives:

#define NPC_REACTION_VAR 7
#include "headers/define.h"

#ifdef DEBUG_MODE
  display_msg("Debug mode enabled");
#endif

• #define / #undef - Define/remove macros
• #include - Include other script files (both "file" and <file> syntax)
• #ifdef / #ifndef / #else / #endif - Conditional compilation

Building

Requirements

• Delphi 12 Athens or newer (Win64 target)
• Windows 10/11

CLI Compiler

1. Open sslc.dproj in Delphi IDE
2. Select Win64 platform
3. Build (Shift+F9)
4. Output: bin\sslc.exe

GUI Version

1. Open FalloutCompiler.dproj in Delphi IDE
2. Select Win64 platform
3. Build (Shift+F9)
4. Output: bin\FalloutCompiler.exe

Usage

CLI

# Compile single file
sslc.exe script.ssl

# Specify output directory
sslc.exe -o output\ script.ssl

# Verbose output
sslc.exe -v script.ssl

GUI

1. Run FalloutCompiler.exe
2. Click Open to load an .ssl file
3. Click Compile to compile
4. View output in the right panel

Architecture

Source (.ssl)
    ↓
[Preprocessor] → Processed source (macros expanded, includes resolved)
    ↓
[TLexer] → Tokens
    ↓
[TParser] → AST (Abstract Syntax Tree)
    ↓
[TBytecodeGenerator] → Bytecode
    ↓
[TINTWriter] → Binary .int file

Unit Structure

Unit	Description
uBuiltins.pas	Built-in function database and opcode definitions
uLexer.pas	Tokenizer for SSL syntax
uAST.pas	Abstract Syntax Tree node types
uParser.pas	SSL parser producing AST
uBytecode.pas	Bytecode generator
uINTWriter.pas	Binary INT file writer
uPreprocessor.pas	C-style preprocessor (#include, #define, etc.)
uCompiler.pas	Main compiler orchestration
sslc.dpr	CLI entry point
FalloutCompiler.dpr	GUI entry point

Compatibility

Generated .int files are compatible with:

• Fallout 2 (original)
• Fallout Et Tu (UP+)
• sfall / mods using standard INT format

Test Scripts

Example scripts are in TestScripts\:

• hello.ssl - Basic display message
• variables.ssl - Variable usage and conditionals
• skillcheck.ssl - Skill check example
• test_include.ssl - Include directive example

License

MIT License

Notes

This is a functional compiler, not a mock implementation. All systems are designed for real Fallout 2 modding workflows.

Recent Changes

See CHANGELOG.md for detailed change history.