Functional Thinking

Chapter 8. Polyglot and Polyparadigm

Functional programming is a programming paradigm, a framework for thinking a certain way about problems and the attendant tools to implement that vision. Many modern languages are polyparadigm (or multiparadigm): they support a number of different programming paradigms, such as object orientation, metaprogramming, functional, procedural, and many more.

Groovy is a multiparadigm language: it supports object orientation, metaprogramming, and functional programming styles, which are mostly orthogonal to one another. Metaprogramming allows you to add features to a language and its core libraries. By combining metaprogramming with functional programming, you can make your own code more functional or augment third-party functional libraries to make them work better in Groovy. In the next section, I show how to use metaprogramming via the ExpandoMetaClass to weave a third-party functional library (Functional Java) seemingly into the core of Groovy.

Orthogonality

The definition of orthogonal spans several disciplines, including mathematics and computer science. In math, two vectors that are at right angles to each other are orthogonal, meaning that they never intersect. In computer science, orthogonal components don’t have any effects (or side effects) on one another. For example, functional programming and metaprogramming are orthogonal in Groovy because they don’t interfere with each other: using metaprogramming doesn’t restrict you from using functional ...