Priorities

[Simon Peyton-Jones]

| Some experts (like Hans Boehm) argue, that concurrency can't be added
to
| the language as a library.
|     http://www.hpl.hp.com/techreports/2004/HPL-2004-209.pdf
| 
| This is true for many imperative programming languages. Haskell seems
| to be an exception:
|
http://www.haskell.org//pipermail/glasgow-haskell-users/2005-December/00
9417.html

The interface can be a library, but (a) what libraries are available is
part of the language definition and (b) it's hard to build a good
implementation without runtime support.  And the nature of the runtime
support depends on what the library interface is.

So a programmer asks "can I write my Haskell' program using
concurrency?".  To answer that question, concurrency needs to be
specified as part of Haskell', just as (say) Integer and its operations
do.  [Of course, we can choose not to; and then Haskell' programs will
be single-threaded.]

Simon