It's Alive! What a Live Object Environment Changes in Software Engineering Practice

TL;DR

This paper discusses the importance of live, interactive object environments in Smalltalk's Pharo, showcasing tools that enhance developer productivity and API evolution, and reflecting on their potential application in other IDEs.

Contribution

It introduces several innovative tools in Pharo that improve live object interaction, debugging, and API management, inspiring improvements in other integrated development environments.

Findings

Tools enable immediate feedback and interaction with objects.

Automated rewriting supports API evolution.

Breakpoints target specific object instances.

Abstract

Tools shape our mind. This is why it is important to have extensible and flexible tools for developers to adapt to their needs. Reasoning about programs in the abstract -- by imagining what objects should look like -- can make it harder to grasp the underlying model. In Smalltalk environments like Pharo, developers work closely with their objects, gaining immediate feedback -- not guessing how they will look like but directly interacting with them. This article presents some tools developers use in Pharo: Inspector custom views for defining specific views and navigation for objects, Microcommits for reverting changes without the need to commit and pull, Xtreme TDD that allows developers to code in the debugger, On the Fly Rewriting Deprecations that support API evolution through automated rewriting of deprecated calls, and Object-Centric Breakpoints -- when a problem cannot be efficiently solved with a dummy trace, developers can use break points that will only halt for a given instance. By showcasing these features that evolved alongside Smalltalk, we invite reflection on how other IDEs could rethink some of their features and improve developers' workflows.