Swift CompilerをSwiftで書いたやつとか、LLVMのSwiftラッパーとかあって面白いですね https://github.com/yanagiba/swift-ast https://github.com/harlanhaskins/Kaleidoscope-Swift https://github.com/llvm-swift/LLVMSwift

swift-ast - A Swift AST parser and visitor that is written in Swift.

Kaleidoscope-Swift - A compiler for the Kaleidoscope sample project, written in Swift

LLVMSwift - A Swift wrapper for the LLVM C API (version 5.0)