Elixir v0.12.0 has been released with improved enumerables, build patterns and welcoming a new member to our team.


In previous versions, the Enumerable protocol was based on reduce/fold, and while it is very efficient for operations like map, reduce and filter, it was sub-optimal for operations that need to halt, like take and take_while, and it made it impossible for operations like zip to be implemented.

In v0.12.0, Elixir’s Enumerable protocol has been extended to allow suspension and halting mechanisms, making operations like take simpler and operations that require interleaving, like zip, possible.

Although most users don’t need to concern with the implementation of the Enumerable protocol, the side-effect is that both Enum and Stream modules have been considerably extended and improved in this release, with more than 15 new functions added to the Stream module.


The tool that received most improvements in this release was Mix. The biggest change is that Mix no longer compiles projects in place but to the _build directory. For example, take the Ecto project that depends on postgrex and poolboy. When compiled, all the artifacts will be placed in the _build directory like this:

└── shared
    └── lib
        ├── ecto
        │   └── ebin
        |   └── priv
        ├── poolboy
        │   └── ebin
        └── postgrex
            └── ebin

For those familiar with Erlang’s OTP, this is similar to the structure used by OTP when releasing your software. So this new structure makes our software one step close to production and guarantee it is designed correctly since day 1.

This approach comes with the :build_per_environment option which, when set to true, creates a different build per environment (dev, test, production or more). Extremely useful when a project compile different artifacts depending on the compilation environment.

Mix has also added support to optional dependencies and improved common patterns, like the usage of umbrella apps.

Welcome, Eric!

With this release, we also want to welcome Eric MJ to the Elixir Team. He has done fantastic work on Elixir, helping us maintain the codebase and working on many of the important features from previous releases and now many more to come.

Eric is also maintainer of both Ecto and Postgrex projects. Which are proving to be very useful to the Elixir community too!

Tidying up

There were other small changes, like additions to the Float module and improvements the to the typespec syntax. To see the full list, please see the CHANGELOG.

Give Elixir a try! You can start with our getting started guide, or check out our sidebar for other learning resources.