It’s been over four months since the last Ceylon milestone was released to the world, and this week saw the release the fourth milestone of Ceylon and its IDE.

The developers describe Milestone 4 - which is nicknamed ‘Analytical Engine’ - as “an almost-complete implementation” of the language. The next major release will be a feature-complete 1.0 beta, promised in January.

Ceylon is the relatively young new JVM language, developed for several years in secret at Red Hat by Gavin King and unveiled to the world last year. It was immediately dubbed by the press as “Red Hat’s Java” and a “Java killer”, leading King to respond that “Ceylon isn't Java, it's a new language that's deeply influenced by Java, designed by people who are unapologetic fans of Java”.

Since then, the team have continued - despite some scathing criticism - to work on the language out in the open, with the source code available on GitHub under a GPL v2 license. New language features added since June include:

• member class refinement (type families)
• class and interface aliases
• union and intersection aliases
• new syntax for package and module descriptors
• assertions
• condition lists
• support for calling super-interface implementations of refined members
• maven repositories
• pluggable command-line tools, git-style
• better support for optional types in Java
• JDK/Jigsaw modules

The Ceylon IDE has also been updated, now able to compile JavaScript (to, say, run on an instance of the oh-so-trendy Node.js), as well as module import completion, a new Repository Explorer view and support for Maven repositories. King wrote on Google+ that his personal favourite feature of M4 is the ability to “write code in the IDE and run it on both the JVM and Node.js, right there, right from within Eclipse”.

Milestone 4 also coincides with an update to Ceylon Herd, the language’s official module repository, which now holds 18 modules - including a new IO Platform Module, which is claimed to provide “the ability to read/write to files, sockets, server sockets synchronously and asynchronously”.

In a message to the Ceylon development mailing list, Red Hat employee and team member Stéphane Épardaud delivered a frank assessment of recent progress, discussing why M4 took “so long” to be released and lambasting the performance of the IDE, JVM compiler and typechecker as “unacceptable”.

However, he added: “I think all the rest we did not just well but great :)”

Photo by sandra.scherer (though it’s of a Cylon, not Ceylon).