Scala.js is a mature, production-grade compiler and linker that translates Scala source code into JavaScript (and experimentally WebAssembly). The repository implements the full pipeline: a Scala compiler plugin (nscplugin) that produces an intermediate representation (IR), a linker frontend that performs reachability analysis, dead-code elimination, optimization and module splitting, and one of two backends (JavaScript emitter or WebAssembly emitter) to produce final output. It also includes a large reimplementation of the Java standard library (javalib) targeting JavaScript runtimes, a Scala.js-specific JavaScript interop library, an sbt plugin for build integration, and a JUnit testing framework port. The architecture is multi-module and cross-version (Scala 2.12/2.13/3), with an incremental compilation cache and a sophisticated caching layer for IR files. The codebase exhibits high craftsmanship: reusable typeclass patterns for NIO buffers, a generic versioning/fingerprinting system for cache invalidation, a monadic tracking mechanism for global variable references in the JS emitter, and an inner optimizer that replaces integer divisions with multiply-shift sequences. However, it also carries some technical drift from deprecated APIs (Closure Compiler, old linker interfaces) and dual implementations for old vs new Scala collections.
The Witchcraft Compiler Collection (WCC) is a binary analysis and modification toolkit focused on ELF executables. It provides three primary tools: wld converts executables to shared libraries, wcc 'unlinks' binaries into relocatable objects, and wsh offers an interactive Lua-scriptable shell for runtime binary inspection and modification. The architecture is modular with shared utilities, leveraging BFD for binary format abstraction, Capstone for disassembly, and Lua/JIT for extensibility. Key capabilities include section/header manipulation, symbol table management, relocation processing, and cross-architecture analysis via Qemu user-mode emulation. WCC demonstrates strong craftsmanship in its Lua-C API extension patterns, sophisticated ELF handling, and modular tool design. The wsh tool's Lua integration exposes binary analysis functions (memory access, symbol lookup, section iteration) through a clean C extension interface. The wld tool implements robust ELF section/header manipulation and relocation processing with careful attention to binary format details. The disassembler wrapper in disasm.c provides multi-architecture support while maintaining integration with WCC's data structures. These components show non-obvious skill in binary manipulation and language embedding. The project shows active maintenance with commits up to 2026 and updated copyright notices. Technical drift is low due to recent updates and compatibility with modern dependencies (Lua 5.3, Capstone). While focused on Linux/ELF and primarily x86_64, the code maintains portability through conditional compilation and abstracted binary handling. The build system uses Makefiles with git submodules for dependency management, and the MIT-licensed codebase includes comprehensive documentation and demonstration materials for security research use cases.