The last months I have been working in a new side project just for fun: Jupiter, a programming language based on Smalltalk. It features a simple bytecode interpreter virtual machine with a mark&sweep garbage collector. Nothing fancy there, but I added some features to the language that I think are worth exploring:

  • A set of simple core types: Numbers ( Just one type of numbers ), Strings, Arrays ( number indexed collections ) and Maps ( String indexed collections ).
  • Immutable data structures.
  • There are no classes. Objects are created copying other objects ( prototypes ). Thanks to immutability no special semantics is needed to achieve this.
  • Code reuse through composition instead of inheritance. Deep hierarchies often are a source of incidental complexity.
  • Unix friendly: Its source code is stored in files, which is not the ‘Smalltalk way’, but this allow easy interaction with other Unix tools, like git, grep, IDE’s/text editors etc..

In my opinion Smalltalk ( and its cousin Self ) are a very interesting programming languages. Seems that nowadays are relegated to niche/academic languages, due to some reasons beyond the scope of this article (although Pharo has a quite active community), nevertheless, I think we can still learn a lot from this ‘old’ technologies.

Contributions are very much welcome. Just open a pull request or an issue in Github :)

Edit 2018-05-18: Check out the brand new Juno IDE, a Smalltalk-like IDE for the Jupiter Programing Language