Dan recently recorded a session about Relic, if you'd like to hear him speak more about the origins of the library, some design choices, and some examples:
- We should aim for simplicity because simplicity is a prerequisite for reliability.
- Simple is often erroneously mistaken for easy. "Easy" means "to be at hand", "to be approachable". "Simple" is the opposite of "complex" which means "being intertwined", "being tied together". Simple != easy.
- What matters in software is: does the software do what is supposed to do? Is it of high quality? Can we rely on it? Can problems be fixed along the way? Can requirements change over time? The answers to these questions is what matters in writing software not the look and feel of the experience writing the code or the cultural implications of it.
- The benefits of simplicity are: ease of understanding, ease of change, ease of debugging, flexibility.
- Simple constructs: Values, Functions, Namespaces, Data, Polymorphism, Managed refs, Set functions, Queues, Declarative data manipulation, Rules, Consistency.
- Build simple systems by: Abstracting (design by answering questions related to what, who, when, where, why, and how); Choosing constructs that generate simple artifacts; Simplifying by encapsulation.
So Clojure is a language that embodies these principles in its design. It's a Lisp, which means that all code is constructed from a very regular expression syntax that has an inherent simplicity and can be quickly understood. It's a functional programming language that provides exceptional tools for minimising mutating state, and it favours working with a small set of data structures and provides a core api with many useful functions that operate on them.
I'd say the result is getting a lot done with a small amount of code, minimal ceremony, true reuse, and the ability to maintain simplicity even as your system's capabilities grow.
https://youtube.com/watch?v=QsEJ5O2e4Es