Whiley v0.3.7 Released!

Thursday, July 7th, 2011

Development has continued at a fairly quick pace since the last release of Whiley.  However, with the impending start of term, things are bound to slow down.  Therefore, I’m making a release now a little sooner that otherwise planned.  This fixes a number of important bugs, finally allowing the compiler to compile my benchmark suite again.

Issues

  • The syntax for synchronous and asynchronous message sends is still causing headaches.  I’ve summarised the main problems in this post.

  • I’m also a little concerned about my rules for implicit coercions.  For example, for a set union operation with type {real}+[int], the right-hand side is implicitly coerced to be {int} and, hence, the result type is {real|int}.  In contrast, things behave slightly differently for an intersection with type {real}&[int].  In this case, the right-hand side is coerced into {real}, not {int}.  The reason for this is that, otherwise, the operation doesn’t make sense — as {real}&{int} would always return the empty set.  These rules seem a little confusing to me, and I suspect I need a clearer (perhaps less powerful) model.

  • I’m a little uneasy over the list append and set union regarding element additions.  For example, in an append of type [int]+int, the right-hand side is added as an element type of [int].  I’m just not sure if I like this or not.

ChangeLog

  • Added first-class char and byte types, which compile down to their primitive equivalents on the JVM. A byte is somewhat different from that in Java, however, as it is not interpreted. That is, it corresponds simply to a sequence of 8 bits. You can perform the usual array of bitwise operations (&, |, ^, << and >>). However, unlike Java, a byte will not implicitly coerce into an int. Instead, you have to use a method which constructs an int assuming some kind of bit representation. Probably the most common one will be le2uint(byte), which generates and unsigned integer from a byte assuming a little endian layout.  More discussion of the byte type can be found in this post.

  • Added support for method pointers.  This allows references to methods to be passed around, just like for function pointers.  An example method pointer type would be int(Reader)::(int) — this indicates a pointer to a method whose receiver is a Reader and which accepts an int parameter and returns an int value.

  • Fixed a lot of bugs.