GHCup vs rbenv

GHCup is a free, open-source installer and version manager for the Haskell toolchain. It installs and manages GHC, cabal-install, Haskell Language Server (HLS), and Stack versions; Stack can also be configured to use GHC versions managed by GHCup. Listed functionality includes a terminal user interface and GHC cross-compilation. Installation guidance covers terminal commands for Linux, macOS, FreeBSD, and WSL2, alongside PowerShell instructions for Windows. The project describes Windows support as being in an early stage and uses a shim wrapper because Windows does not properly support symbolic links. On macOS, GHCup may prompt for command line tools; Windows setup includes msys2. The installer should be run as a non-root user on Unix-like systems and a non-admin user on Windows. GHCup relies on precompiled binaries, so compatibility can depend on the distribution and libraries such as libtinfo. WSL1 and macOS versions earlier than 10.13 are unsupported. Some ARM binaries are experimental: Stack and HLS on Linux ARM, and HLS bindists on macOS aarch64. Configuration can be stored in ~/.ghcup/config.yaml, with command-line options taking precedence.

rbenv has no write-up on Specifiction yet; its figures are above.