Bottom Up vs Top Down Design in Clojure
Mark Bastian at Clojure/conj 2015
The standard approach to developing a program or API in Object Oriented Programming is to take a "Top Down" approach in which the modeler starts with the domain at large and decomposes this domain into smaller pieces, generally in the form of classes. This often results in complex, interconnected type hierarchies. In Clojure, the standard approach is to design "Bottom Up," in which the developer first models an actual domain instance using Clojure data structures and then writes simple functions for manipulating the domain data. These functions can then be recombined and composed into more powerful functions. Ultimately, a program emerges. This approach has several advantages including: 1) bottom up functions have more reuse, 2) bottom up design allows for immediate domain modeling using actual data, 3) it is easier to reason about what is going on in bottom up design. This talk will first describe the two approaches, then it will walk through the development of a program using bottom up design in Clojure, culminating in a live demonstration of the program. Attendees will gain an appreciation for this technique and see it in action. In particular, they will see how Clojure is especially well suited to this approach.
About the speaker: Mark Bastian has been developing applications in the Java ecosystem for over 10 years. He started doing Scala and Functional Programming over 5 years ago and has been programming in Clojure personally and professionally for over a year. He is a programming languages and paradigms enthusiast and loves finding and evangelizing the best practices from all the languages and paradigms he encounters. In his spare time he blogs about Clojure and Functional Programming at http://fn-code.blogspot.com.
About the speaker: Mark Bastian has been developing applications in the Java ecosystem for over 10 years. He started doing Scala and Functional Programming over 5 years ago and has been programming in Clojure personally and professionally for over a year. He is a programming languages and paradigms enthusiast and loves finding and evangelizing the best practices from all the languages and paradigms he encounters. In his spare time he blogs about Clojure and Functional Programming at http://fn-code.blogspot.com.