Cons T. Åhs

Developer in Erlang/OTP Team, Borderline Senior

Cons has a long history of writing code, with Lisp and functional languages from early days. Worked with formal methods, language implementation and lecturing at Uppsala University and escaped to a life of speech synthesis, music notation, graphics, networks, imaging, online poker, network configuration and more language implementation.

Currently falling down the rabbit hole at the Erlang/OTP team at Ericsson, working with language aspects, the compiler and ssh.  In parallel with this,  very fond of typed languages, testing, tooling and targeting the BEAM with yet another language.

Past Activities

Cons T. Åhs
Code BEAM Europe 2022
20 May 2022
10.35 - 11.20

Evolving Erlang/OTP Feature by Feature

With the release of OTP25, support for selectable features in the language and the runtime will be added. This means that extensions and changes to the language and/or runtime system can be used selectively. One benefit is the possibility to try out features without affecting existing code, even for backwards-incompatible changes. This talk will be a deep dive into the ideas and implementation behind the support for features. As an extended example, we will show how this support is used to add Value-Based Error Handling (EEP49) as the first experimental feature.


Stake out a path forward, evolving Erlang/OTP without forcing developers to rewrite legacy code.


- Developers using Erlang/OTP, both those wanting new features and those who don't.

- Managers of the same

Hakan Mattsson / Cons T. Åhs
Code BEAM STO 2019
16 May 2019
10.45 - 11.30

LUX - an expect like test tool

LUX is an open source test tool written in Erlang and mostly used for testing Erlang code. But as a user of the tool you do not need to bother about that. It provides a highly automated test environment where it is simple to perform concurrent orchestration of text based interfaces such as shells, interpreters, CLI's etc. Some major design goals are that the test programs should be easy to understand, easy to analyse the outcome of the tests, easy to debug and trace.


Share a very useful test tool used by Cisco.


Developers, integration testers, system testers.