Jura: A Successor to Java John Winn, December 2003

[Sourceforge project page]

Jura is a new language which I have invented as a successor to the Java language.  There are so many languages out there that the decision to create a new one should never be taken lightly, but this is why we need a successor to Java. 

This online document summarises the Jura language and gives a number of examples of Jura source code.

Key features of Jura

The Jura language has a number of key features:

• Jura is a data language: it can be used to describe any structured data, including source code.
• Data/program equivalence: the Jura representation of some structured data and the source code required to programmatically create an instance of that data are one and the same thing.
• Programmatic design patterns: these are design patterns which can be imported and implemented automatically. 
• Generics: allows generation of classes from generic templates. Generic templates in Jura are not limited to changing the type of methods, parameters etc. but can change any aspects of a class, including implementation. 
• Abilities: these are tiny interfaces which allow common functionality to be declared at a fine degree of granularity, so allowing the creation of highly reusable algorithms.
• Transforms: allow transformation of object graphs in a similar manner to XSLT (except clean and object-orientated) implemented using only a small set of programmatic design patterns.
• Restricted types: allows restrictions to be added to types, such as enforcing that an Integer is in a particular range or a String satisfies a particular regular expression. 

There are some new languages out there which share some of the design goals of Jura (see the Extended Java and OO languages sections on this page).  Whilst some of these implement some of the above features, none implement them all in a single, clean, consistent language.  Unhappily, many new languages add features which I consider dangerous (or at best unhelpful) as they go against the principle of declarative programming (you should write only what you mean). I currently consider Aspect Orientated Programming in this category - programmatic design patterns and transforms can do the same job but in a clean, object-orientated way.

A prototype Jura compiler

I have created a prototype Jura compiler which is released under the Lesser GPL licence. This means that the compiler itself is open source but that it can be used to to compile either open source or proprietary programs. The compiler turns Jura source code into Java classes and so allows Jura classes to be used from Java and vice versa.