ghcup/README.md

GHC up

Installs a specified GHC version into ~/.ghcup/ghc/<ver>, and places ghc-<ver> etc. symlinks in ~/.ghcup/bin/. Additionally allows to manage currently selected ghc via unversioned symlinks.

This uses precompiled GHC binaries that have been compiled on fedora/debian by upstream GHC.

Alternatively, you can also tell it to compile from source (note that this might fail due to missing requirements).

In addition this script can also install cabal-install.

Note: this project is in early stage and may not work on all distributions yet!

Table of Contents

• Why
• Installation
• Usage
• Contributing
• TODO
• Known problems

Why

cabal new-* manages your haskell packages, but not GHC versions, since it follows the unix philosophy. Unfortunately system GHC versions are often either outdated or cannot be installed in parallel with proper symlink management on many distros. This tool tries to fill that gap and be fairly distro-agnostic.

Inspired by rustup.

Installation

Just place the ghcup shell script into your PATH anywhere.

E.g.:

mkdir -p ~/.local/bin
curl https://raw.githubusercontent.com/haskell/ghcup/master/ghcup > ~/.local/bin/ghcup
chmod +x ~/.local/bin/ghcup

Then adjust your PATH in ~/.bashrc (or similar, depending on your shell) like so, for example:

export PATH="$HOME/.cabal/bin:$HOME/.ghcup/bin:$HOME/.local/bin:$PATH"

Usage

See ghcup --help.

Contributing

• PR or email
• this script is POSIX shell
• use shellcheck and checkbashisms.pl from debian devscripts
• whitespaces, no tabs

TODO

• FreeBSD support (#4)
• Make fetching tarballs more robust (#5)
• More code documentation
• Allow to compile from source (#2)
• Allow to install cabal-install as well (#3)

Known problems

Precompiled binaries

Since this uses precompiled binaries you may run into problems with ncurses and missing libtinfo, in case your distribution doesn't use the legacy way of building ncurses and has no compatibility symlinks in place.

Ask your distributor on how to solve this or try to compile from source via ghcup compile <version>.

Unreliable download location

There is no single reliable URL where to download future GHC binary releases from, since the tarball names contain the distro name and version they were built on. As such, we cannot foresee what will be the next tarball name.

In such a case, consider to update this script via ghcup self-update.

Compilation

Although this script can compile GHC for you, it's just a very thin wrapper around the build system. It makes no effort in trying to figure out whether you have the correct toolchain and the correct dependencies. Refer to the official docs on how to prepare your environment for building GHC.