Whiley v0.2.9 Released!

Well, here’s version 0.2.9.   This includes numerous bug fixes, and several major feature updates:

• Support for recursive algebraic datatypes

• Improved support for type testing, particularly of recursive types

• Syntax of function declarations has changed slightly to use where instead of requires + ensures.  See this post for more on why.

However, there remains a long list of outstanding issues:

• Compile-time checking of recursive constrained types is a problem in some cases.  See this post for more.

• Type inference doesn’t work in all cases either.

• Boolean lists remain a problem.

At this stage, I am faced with some difficult choices.  The current design is getting overly complex and, frankly, I don’t believe it will go the distance.  A new design is really needed that will dramatically simplify many aspects of the process.  My current thinking on this is to move towards a simplified intermediate language, similar in some ways to Java bytecode.  The advantage of this is that it would significantly reduce the number of cases that need to be processed; it would also provide a nice interface between the front-end and the back-end, helping to separate them and improve overall modularity.