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Haskell 2010 Announced
paltemalte writes "Simon Marlow has posted an announcement of Haskell 2010, a new revision of the Haskell purely functional programming language. Good news for everyone interested in SMP and concurrency programming."
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I'm not sure what you mean by "recursive style", but the biggest commercial users of functional programming languages tend to be companies behind high-traffic websites that need to handle a lot of concurrent requests. Facebook developed their real-time chat application in Erlang, for instance, and Twitter uses Scala to handle its message queue.
> I'm not sure what you mean by "recursive style",
Look at Quicksort in Haskell :
qsort [] = []
qsort (x:xs) = qsort (filter (= x) xs)
This is what I mean, no loops, recursion. I used Prolog and ML to solve logic problems and it is pretty handy. Prolog is especially suited for solving logic problems ( "logic programming" ).
Everything I write is lies, read between the lines.
That's not true unless you are using a different definition of "functional" than I am. I can't comment on Scala since I haven't used it, but Erlang is indeed a functional language. It is not a _pure_ functional language, as Erlang does have some mechanisms for manipulating mutable, global state and message passing, but it's at least as functional as a lot of other language that are widely regarded as "functional programming languages" such as Lisp and ML.
Amdahl's law is not like Moore's "law". Amdahl's law is an observation of mathematics. You can't ever get around the fact that if you increase the performance of 90% of the instructions in a program, you still have to deal with the other 10%. Even if you increase the performance of 90% of the instructions by 100x or something large, if the other 10% take a long time (like disk access) its going to kill your performance.
Erlang and Scala are both languages designed to support programming in a functional style, and both are "recursive style" languages in that they optimize tail calls generally (Erlang) or at least in the most important case of self-recursive calls (Scala) and thus make tail-recursive (or, in Erlang's case, more general tail calling with unlimited depth) programming styles efficient.
Neither is a pure functional programming language, true.
I would add a couple other "must have" features in functional languages:
* The ability to pass a function as an argument to another function (i.e. higher order functions, like qsort in the C standard library).
* Support for a points-free programming style in which things can be passed from one function to another without naming them.
Some other features that perhaps aren't technically required but make functional programming a lot easier:
* Closures, local function definitions, garbage collection, partial evaluation of function.