bachelor-thesis/proposals/proposal_functional_introduction.md

Functional Go

Situation

With the rise of Javascript, Rust, and Go, the functional programming paradigm has gained popularity too. Though none of these programming languages are purely functional, they all share the common feature of having the possibility to use functional concepts. However, a lot of programmers struggle initially with the concept of functional programming. Learning a purely functional programming language is extremely useful to gain familiarity with these concepts. Purely functional programming languages like Haskell though are not known for their beginner-friendliness. What makes learning a functional language difficult is that not only does the programmer have to learn an entirely different paradigm, but also a syntax that is uncommon for people coming from imperative or object-oriented languages.

Objective

The objective is to ease the entry into functional programming by providing a "harness" for Go that enforces a purely functional style. This harness can either be a separate stand-alone tool (like gofmt or gopls) or built into the Go compiler directly. The functional Go code could still be valid Go code, but the harness could also apply simple transformations to the code to make it more performant. Things to consider while implementing that harness would be immutability (without introducing unnecessary complications), the possibility to make functional Go code run and / or compile with regular Go code (code translation?). Another possibility would be to implement something like "functional-check". What shellcheck is to shell-scripts, funccheck is to Go code. It lints existing Go code and points out the bits that are not functional, displaying rules and examples. While being conceptually simpler, this would leave most options to the programmer.

In the end, functional Go should be syntactically familiar to people that have worked with Go (or C in that regard). With that, one can learn the concepts related to functional programming, without also needing to learn a new language and syntax.