To easily install Crystal on macOS you can use Homebrew.

brew update
brew install crystal

You should be able to install the latest version from homebrew. Crystal’s core-team help maintain that formula.

Alternative there are .tar.gz and .pkg files in each release targeted for darwin. See Install from a tar.gz

Upgrade

When a new Crystal version is released you can upgrade your system using:

brew update
brew upgrade crystal

Troubleshooting

On macOS 10.14 (Mojave)

If you get an error like:

ld: library not found for -lssl (this usually means you need to install the development package for libssl)

you may need to install OpenSSL and link pkg-config to OpenSSL:

brew install openssl
export PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/usr/local/opt/openssl/lib/pkgconfig

As with other keg-only formulas there are some caveats shown in brew info <formula> that shows how to link pkg-config with this library.

The Crystal compiler will by default use pkg-config to find the locations of libraries to link with.