sys4lang

This repository contains a collection of tools for AliceSoft's System 4 game engine. It integrates a compiler (sys4c), a decompiler (sys4dc), and a language server (sys4lsp).

Games up to Heartful Maman (early 2017) are currently supported. Games from Beat Valkyrie Ixseal onwards are not yet supported.

Components

• sys4c (Compiler): A compiler for System 4. This is primarily intended for building source files that were decompiled using sys4dc. Unlike AinDecompiler, it focuses on full builds and cannot modify only specific functions in an existing .ain file.

• sys4dc (Decompiler): A decompiler for System 4 .ain files.

• sys4lsp (Language Server): A language server for the System 4 programming language.

Installation

Pre-built binaries for Windows (x64) and Linux (x64) are available on the GitHub releases page.

Building from Source

To build and install the tools from source, you need to have OCaml and opam installed. Then, run the following commands:

$ git clone https://github.com/kichikuou/sys4lang.git
$ cd sys4lang
$ opam install . --deps-only --with-test
$ dune build
$ dune install

Usage

The typical workflow is to decompile a game, edit the source code, and then recompile it.

1. Decompile

Use sys4dc to decompile an .ain file:

$ sys4dc -o src SengokuRance.ain

2. Edit

Edit the decompiled source code with editor support. If you're using Visual Studio Code, you can install the System4 language extension to get features like diagnostics, hover, and jump to definition. The language server (sys4lsp) is used automatically by the extension.

3. Compile

Use sys4c to build the source files:

$ sys4c build src/SengokuRance.pje

Command Reference

sys4c

sys4c is the System 4 compiler. It has two subcommands.

sys4c build PROJECT

Build a System 4 project from a .pje project file. This is the typical way to compile a decompiled game.

$ sys4c build src/SengokuRance.pje

Options:

Option	Description
--output-dir OUTPUT_DIR	Override the output directory specified in the .pje file.
--no-debug-info	Do not write the debug_info.json file.

sys4c compile SOURCES...

Compile one or more .jaf source files (and optionally .hll library files) directly, without a project file.

$ sys4c compile -o out.ain foo.jaf bar.jaf

Options:

Option	Default	Description
-o, --output OUT_FILE	out.ain	Output .ain file path.
--ain-version MAJOR	4	Major version of the output .ain file.
--ain-minor-version MINOR	0	Minor version of the output .ain file.
--import-as HLL_NAME=NAME		Import an .hll file under a different name. Can be specified multiple times.
--input-encoding ENCODING	UTF-8	Input file encoding: UTF-8 or Shift_JIS.

sys4dc

sys4dc decompiles a .ain file into JAF source files.

$ sys4dc -o src SengokuRance.ain

Arguments:

Argument	Description
AIN_FILE	The .ain file to decompile.
FUNCTION	Optional. Restricts the output to a single function. With --disassemble/--disassemble-raw, only this function is disassembled; otherwise, detailed information about its decompilation process is printed.

Options:

Option	Description
-o DIRECTORY	Output directory. Use - to print all output to stdout. Defaults to the current directory.
--address	Print bytecode addresses as comments in the output.
--disassemble	Disassemble the code section instead of decompiling.
--disassemble-raw	Like --disassemble, but without resolving identifiers or generating labels (raw listing with addresses).
--move-to-original-file	Move overridden functions to the files where they were originally defined. Useful for mods created with AinDecompiler.
--continue-on-error	Continue decompilation even if an error is encountered in one function.

sys4lsp

sys4lsp is a Language Server Protocol server for the System 4 language. It is normally launched automatically by an LSP client (such as a VS Code extension) and communicates over stdio.

$ sys4lsp [PJE_FILE]

The optional PJE_FILE argument specifies the .pje project file to load. It is used as a fallback when the LSP client does not provide a pjePath via the initializationOptions of the initialize request.

Initialization Options

The LSP client may pass the following fields in the initializationOptions object of the initialize request:

Field	Description
pjePath	Path to the .pje project file to load. Takes precedence over the command-line argument.

Credits

The sys4c compiler and sys4lsp language server are derived from the original sys4c compiler by @nunuhara.