Frege
code.google.com
code.google.com
Can anyone explain the interest of this to someone unfamiliar?
android, desktop, web are some examples.
But (the following point applying beyond the scope of Frege, and not intended to say anything negative about Frege) it is disappointing that there isn't better interop between JVM and non-JVM languages, so that people are so frequently forced to choose and to duplicate effort between the two worlds. For example, Frege being similar to Haskell, but using Java APIs - it is disappointing that there can't be a cleaner join between the worlds.
Surely the whole point of being on the JVM is that you can use the vast amount of software written for java.
Maybe it can. But does it make sense? For example, you'd need a library that emulates the C stdlib functionality that is used in Haskell.
There are more subtle points. For example, in Haskell, you can throw an exception in another thread. You can't do that with JVM threads. I am not sure what it would take to make a JVM runtime system that supports this.
But observe that the more runtime code you have that keeps up the illusion of running a Haskell-RTS, POSIX, C stdlib world, the less you will be able to interact with the rest of the JVM. For, your Strings are not Strings, but lists of characters, your Boolean is a sum type, your Filedescriptors are some abstractions nobody else understands, your threads are not JVM threads, but something that can be interrupted form other such somethings, ... and so on and on.
If there is one, and if it were very different from Haskell, people would complain: Couldn't you make it more like Haskell, so that people don't need to learn the many differences?
If there is one, and if it is not very different from Haskell (so much so, in fact, that many Haskell sources will just compile), people will be disappointed because it is not standard Haskell. In fact, the fewer differences there are, the more complaints.
If it were fully fledged Haskell-2010, people would complain: Where is GHC extension XY? How is Haskell-2010 any good these days?
You never can make everyone happy, no matter what you do.
It just so happens that what one sees as a good reason is pointless for somebody else.
The repo contains an example folder: https://github.com/Frege/frege/tree/master/examples
And, of course, the compiler is itself written in Frege.
This mentions Odersky's pizza, which (I think) was the first implementation of generics on the JVM.
I think there other things talking about MSR's effort to port haskell to the CLR