Gentoo Linux includes the Crystal compiler in the main overlay.
You might want to take a look at the available configuration flags first:
# equery u dev-lang/crystal
[ Legend : U - final flag setting for installation]
[ : I - package is installed with flag ]
[ Colors : set, unset ]
* Found these USE flags for dev-lang/crystal-0.18.7:
U I
- - doc : Add extra documentation (API, Javadoc, etc). It is recommended to enable per package instead of globally
- - examples : Install examples, usually source code
+ + xml : Use the dev-libs/libxml2 library to enable Crystal xml module
+ - yaml : Use the dev-libs/libyaml library to enable Crystal yaml module
su -
emerge -a dev-lang/crystal