NOTE: IL2X is being re-investigated for CPU targets

https://github.com/reignstudios/IL2X
This would end up making CS2X mostly for GPU targets.

CS2X (Under development)

Transpiles a C# subset to non .NET languages, platforms, runtimes and enviroments. (Powered by Roslyn)

CS2X is activily being tested in the development of the Orbital-Framework:
https://github.com/reignstudios/Orbital-Framework
This provides real-world tests and as things progress more features will tested and supported here.

WASM Demo

Renders a 1280x720 image then prints how long it took in seconds.
http://reign-studios.com/wasm/cs2x/ray-trace-benchmark/cs2x.html

Goals

This project will focus on transpiling a C# subset with a modified type system for writing CPU and GPU programs.

Custom Standard lib(s) for various targets.
Documentation

CPU targets

C89
- Native C performance
- C89: modern, legacy and embedded platforms (x86, MIPS, SPARC, RISC-V, PPC, M68K, AVR, etc)
- CC65: 6502 platforms (Atari, C64, NES, Apple II, etc)
- SDCC: Many targets (ColecoVision, ZX Spectrum, etc)
- z88dk: Z80 platforms
LLVM
LLVM IR => Assembly: CP1610 (Intellivision)
LLVM IR => Assembly: Intel 8048 (Magnavox Odyssey 2)
LLVM IR => Retarget: Custom assembly targets (FPGA CPU, 16bit bytes, etc)
Java
Kotlin
javaScript
Python
ActionScript

GPU targets

HLSL (DirectX Shader Assembly Language) [D3D9.0c +]
ALS (DirectX Shader Assembly Language) [D3D8.0 - D3D9.0c]
GLSL (OpenGL shading language) [OpenGL2.0 / GLES2 +]
ARB (ARB assembly language) [legacy / homebrew systems]
CG (Cg programming language) [PSVita, Nvidia / other]
PSSL (PlayStation Shader Language) [PS4]
MSL (Metal Shading Language) [macOS / iOS]
AGAL (Adobe Graphics Assembly Language)
Custom: Plugin system

Primary Project libraries

CS2X.Core: .NET transpiler lib
CS2X.CLI: CLI interface for CS2X.Core
CS2X.Analyzer: C# syntax analyzer to limit unsuported features.
CS2X.CoreLib: Portable CoreLib subset

How does it basically work?

C89
- Each executable gets built to a single '.c' source file including all dependencies.
- String literals on embedded devices, cartridges, etc can be stored in program memory / ROM to save ram.
- All GC methods are agnostic allowing any built-in or custom GC backend.
Other: TODO

Performance

Almost zero performance loss. C# code will generate in a manner as if hand written in the target language in many respects. There are a couple key differences in the CS2X runtime / type system vs .NET CLR

Structs are not part of the object system as they are in the .NET runtime.
- No auto boxing for value types are supported (.NET has many easy to fall in syntax performance pitfalls here).
- System.Object can never equal a 'struct', 'enum' or 'primitive' type.
- Virtuals like 'MyStruct.GetType()' or 'MyEnum.GetType()' give compile time errors (use typeof instead).
- Cannot bind a delegate to a structs non-static method.
Interfaces are considered 'type-classes' and are compile time only.
- Used for generics or general code consistency.
- No casting to them or variable declarations of them.
No up-casting performance loss in C and down-casting checks can be disabled for C output.
Auto-Marshalling of managed types not supported.
- Varies to much between platforms in contrast to .NET making writing portable code confusing.
- Auto string marshalling has way to many implicits that depend on to many factors to keep track of.
- Redundant allocations. If you want to pass the same string multiple times in multiple methods for example auto-marshaling it everytime doesn't make sense. Its far better to be explicit here and make that obvious by pre-marshalling the type once.
- Portability. Forcing PInvokes to be used this way ensures code functions the same in all runtimes.

Building

Prerequisites
- Visual Studios 2019 (VS for Mac / MonoDevelop or VSCode have not yet been tested)
- .NET Core 5
- .NET Compiler Platform SDK
Run: CS2X.Core.Test proj in VS. This will build "PortableTestApp.csproj" to "TestOutput" folder
NOTE: Early stages so nothing else is supported yet.

kobi2187 / CS2X