Configuration Languages can also be functional by Till Schröder

August 16, 2023

Till Schröder presents the challenges of configuration files in software development, including their role in major outages and the lack of tools for ensuring their correctness. Till then introduces the concept of functional configuration languages, such as JavaScript and YAML, to improve readability and maintainability. However, he also warns of potential security vulnerabilities and complexities in using YAML. The speaker then explores Toml as an alternative and the benefits of using type annotations and type checking in configuration languages. He also demonstrates the use of functions and hash functions in a functional configuration language called Dhall, which provides safety guarantees and efficient editing.

Configuration Languages can also be functional: A comprehensive overview

In his enlightening presentation, Configuration Languages can also be functional, Till Schröder delves into these challenges and introduces the concept of functional configuration languages as a solution to revolutionize configuration management.


Addressing configuration complexity

Till begins by highlighting the critical role of configuration files in software development, emphasizing their susceptibility to bugs and security vulnerabilities. Drawing from his personal experiences with large configuration files in C++ build systems and AWS CloudFormation, he underscores the lack of tools and practices for ensuring the correctness and manageability of configuration files compared to code files. This sets the stage for exploring functional configuration languages as a means to address these challenges.


Navigating configuration language landscape

Throughout the presentation, Till navigates through various configuration languages, analyzing their strengths, weaknesses, and implications for configuration management. From the complexities and vulnerabilities of YAML to the potential security risks of interpreting untrusted code in AWS CloudFormation, he sheds light on the limitations of existing solutions and the need for more robust alternatives.


Introducing functional configuration languages

Central to Till ‘s presentation is the exploration of functional configuration languages, such as Dhall, as a promising solution to configuration management woes. He highlights the benefits of Dhall’s structured approach, type annotations, and type checking, which enable safer, more readable, and maintainable configuration files. By leveraging functional programming principles, Dhall offers a comprehensive solution to configuration management, empowering developers to create secure and efficient configuration files.


Ensuring security and reliability

Till emphasizes the importance of security and reliability in configuration management, particularly in the context of functional configuration languages. He discusses Dhall’s security features, including purity, secure imports, and type checking, which mitigate the risks of security vulnerabilities and ensure the integrity of configuration files. By embracing total programming languages like Dhall, developers can achieve complete type checking and reliability, minimizing the potential for errors and exploits.



Till Schröder’s presentation on functional configuration languages offers invaluable insights into the challenges and solutions in configuration management. By advocating for the adoption of functional programming principles and robust configuration languages like Dhall, he provides a roadmap for developers to revolutionize their approach to configuration management. With a focus on security, reliability, and efficiency, functional configuration languages pave the way for safer, more manageable, and more resilient software systems.


Additional resources

Check out more from the MeetUp Func Prog Sweden. Func Prog Sweden is the community for anyone interested in functional programming. At the MeetUps the community explore different functional languages like Erlang, Elixir, Haskell, Scala, Clojure, OCaml, F# and more.