Ceylon M4 was released back at the end of October, more than three months ago, so you might be wondering what the hell have we been up to and where in hell is that M5 release we promised! At the very least you deserve a progress report.

So what's going on is that M5 has gone quite a bit off the roadmap. This was kind of my last chance to revisit some design choices I made a couple of years ago before there was any kind of compiler for Ceylon or libraries written in Ceylon. Inevitably, there were some things that seemed like a good idea at the time, but:

• I never really managed to sell to everyone else,
• we ended up falling out of love with, or
• just didn't quite work out in practice once we started writing real code.

This was really our last opportunity to fix things like that, so we've lost some time there.

Additionally, there was one thing, namely tuples, that I didn't think we were going to need, that we did wind up needing, and accommodating it elegantly into the language was actually somewhat disruptive. This also cost some time, and there is still some unfinished work there.

Finally, we decided to throw away almost all the human-compiled code in the language module and compile it with the Ceylon compiler instead. That was hard work, but it sure makes as feel a lot more secure and saves us a lot of pain when we add things to the language module.

So the bad news is that, given the above, some functionality is going to slip from M5, and therefore M5 will not be a feature-complete implementation of the language. In particular, it wont have support for:

• annotations,
• serialization, or
• the metamodel (reflection).

It will have the following new features:

• tuples
• direct interop with native JavaScript APIs via the new dynamic block (more on this in a separate post)
• the : operator
• verbatim strings
• fat arrow => abbreviation for defining single-expression functions
• the late annotation
• binary and hexadecimal numeric literals
• defaulted type parameters
• experimental support for reified generics
• many miscellaneous minor improvements to the syntax and typing rules of the language
• ceylon.time module
• ceylon.net.httpd package (a HTTP server)
• the compose() and curry() functions

(Please don't try to tell me that's not a pretty impressive list!)

I also finally found the time to give the language specification some love, after several months of neglect, so it's now up to date with all this new work. Ceylon is a better language now, I'm certain of it.

Well, I've a little more bad news: M5 is still not ready :-(

• Stef's currently putting the finishing touches on his initial implementation of reified generics,
• David's working on some performance issues with compilation inside the IDE that we would prefer to see fixed in M5,
• Roland Tepp is finishing off work on the initial release of ceylon.time,
• Matej Lazar is doing some API improvements to ceylon.net.httpd, and
• there's still a bunch of backend bugs that need fixing.

Bear with us. It's frankly very painful for us to have not had a release in almost four months, but in a funny way that's more of a sign of how close we are now to delivering something you can really use to write real applications.