Serializing and deserializing polymorphic JSON into Go structs

Introduction

It is quite common in object-oriented languages to rely on polymorphism to restrict the range of types that can be used in a particular case. This can be achieved either by using an interface or by subtyping.

In Go we can use an interface to achieve polymorphism, but subtyping however is not possible as there is no traditional notion of inheritance (e.g. via subclassing). We can embed a struct within another, but that doesn’t achieve the same effect as subtyping.

Example

Let’s take an example that is commonly used to describe this problem. A fleet of vehicles which can be either cars, trucks, bikes or any special case of vehicle we can imagine. …


Photo by veeterzy on Unsplash

Recently I’ve been working on a Trie implementation and I was a surprised and delighted from the simplicity of the data structure.

The first time I came across the Trie data structure, I was looking to solve a problem where a typeahead field had a really large dictionary to query and would choke every time the search was triggered. After stumbling upon John Resig’s JavaScript implementation I wanted to see how it would translate in Go.

So without further ado, I’d like to share with what I found interresting about the Go version.

The data type

type Node map[rune]Node

Using self-referential type definition we are able to describe our tree nodes with nothing more than just built-in types. …


Recently, I found myself trying to implement a mechanism, able to evaluate expressions. Essentially what I needed was a binary expression tree. I used Go for this project, and quickly came to a delightful surprise that using Go’s extremely powerful interface mechanisms, it became extremely easy to implement and extend.

Before we dive in

From Wikipedia:

A binary expression tree is a specific application of a binary tree to evaluate certain expressions. Two common types of expressions that a binary expression tree can represent are algebraic and boolean. These trees can represent expressions that contain both unary and binary operators.

The leaves of a binary expression tree are operands, such as constants or variable names, and the other nodes contain operators.

Alex Kalyvitis

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