Pharo, short for Pharo Smalltalk, was created in 2008 as a fork of the Squeak Smalltalk project by Stéphane Ducasse, Damien Cassou, and a team of contributors. Pharo is a modern, open-source, object-oriented programming environment and language that focuses on live programming, dynamic development, and software research. It is used for software engineering, web applications, research prototypes, education, and embedded systems. Developers can access Pharo via the official site: Pharo Official Downloads, which provides the image-based environment, virtual machine, libraries, and documentation for Windows, macOS, and Linux platforms.
Pharo exists to provide a highly interactive and dynamic development environment where programmers can modify and inspect live objects, test code immediately, and evolve software continuously. Its design philosophy emphasizes simplicity, readability, live coding, and object-centered programming. By combining a minimalistic core with powerful reflection and live object inspection, Pharo solves the problem of slow edit-compile-run cycles common in traditional programming environments.
Pharo: Objects and Classes
Pharo is built entirely around objects and classes, where every value, data structure, or code entity is an object.
Object subclass: #Person
instanceVariableNames: 'name age'
classVariableNames: ''
package: 'MyPackage'.
person := Person new.
person name: 'Alice'.
person age: 30.
Transcript show: person name; nl.Objects encapsulate state and behavior, while classes define structure. This object-centric approach enables live interaction and modification of programs, conceptually similar to Smalltalk and FScript.
Pharo: Methods and Messaging
Pharo uses message passing between objects to invoke behavior instead of calling functions or procedures directly.
Person>>greet
Transcript show: 'Hello, ', name; nl.
person greet.Messaging allows loose coupling and flexible communication between objects, making systems easier to extend and modify. This is conceptually similar to method calls in Smalltalk or dynamic dispatch in JavaScript.
Pharo: Live Programming and Workspace
Pharo provides a live workspace where developers can interact with objects, test snippets, and inspect running code.
workspace := Workspace new.
workspace evaluate: 'Transcript show: ''Live code running''; nl.'Live coding allows immediate feedback and debugging without restarting the system. This interactive approach is conceptually similar to live object exploration in FScript and interactive shells in Smalltalk.
Pharo: Tools and Ecosystem
Pharo includes integrated tools for version control, refactoring, code analysis, UI building, and testing.
Metacello new
baseline: 'MyProject';
repository: 'github://user/repo';
load.These tools facilitate project management, dependency handling, and collaborative development. This ecosystem is conceptually similar to Smalltalk-based environments in Smalltalk and scripting tools in FScript.
Pharo is used in research, education, web development, software prototyping, and industrial applications. Its object-oriented, live, and dynamic nature makes it ideal for experimentation, rapid development, and understanding complex software behavior. When combined with Smalltalk, FScript, and Seaside, Pharo provides a highly interactive and productive environment for software exploration and development.