eselect module for managing Rust compiler symlinks

User's guide

eselect-rust allows you to easily switch between different Rust implementations.

List available implementations:

eselect rust list

Set implementation you need:

eselect rust set TARGET

where TARGET is the target number or name as listed in the list command.

Unset symlinks:

eselect rust unset

Packager's guide

Every package that installs Rust implementation on Gentoo should collaborate with this eselect module.

Target and target suffix

To register your package in eselect-rust you need to install /etc/env.d/rust/provider-TARGET file, where TARGET is your target name as it will be show by eselect.

To differentiate symlink targets installed by different packages target suffix is used. Target suffix is the part of target name that follows first - or target name itself if it includes no - characters. To split out target suffix, command cut -d- -f2- is used. Some examples:

TARGET                  TARGET SUFFIX

rust-1.0.0_beta2        1.0.0_beta
rust-bin-1.0.0_beta2    bin-1.0.0_beta2
somecrazyimpl           somecrazyimpl

Symlinks

Rust implementation package can include a number of symlinks that can be managed by eselect. Package itself should install only symlink targets named PATH/NAME-TARGET_SUFFIX. Where PATH/NAME is the future symlink location and TARGET_SUFFIX is described in the previous paragraf.

Example. If package wants to have symlinks /usr/bin/rustc and /usr/bin/rustdoc and its target suffix is 1.0.0_beta, it should install these files:

/usr/bin/rustc-1.0.0_beta
/usr/bin/rustdoc-1.0.0_beta

The main symlink that eselect-rust manages is /usr/bin/rustc. It is the symlink that every package should have and it determines what implementation is shown as active by eselect.

To determine other symlinks that package sets, eselect-rust uses the content of the /etc/env.d/rust/provider-TARGET file. This file should contain symlink paths one per line. If this file is empty, eselect-rust behaves as its content were one line /usr/bin/rustdoc.

Example. If you want to have symlinks /usr/bin/rustc, /usr/bin/rustdoc and /usr/bin/rust-gdb, then /etc/env.d/rust/provider-TARGET should contain:

/usr/bin/rustdoc
/usr/bin/rust-gdb

Note, that /usr/bin/rustc should not be listed, as it is always managed by eselect.

Notes

eselect-rust automatically prepends every path with ${EROOT} variable.