Arrow syntax

Ross Paterson
Sat, 23 Aug 2003 11:45:19 +0100

On Fri, Aug 22, 2003 at 08:34:55AM +0100, Simon Peyton-Jones wrote:
> No, it's only in the HEAD, which you may be able to pick up from a
> development snapshot, or you can build from source.  It'll be in 6.2
> I'm not certain if the syntax is identical; Ross will know

It's mostly the same -- the big difference is that the higher-order
version of a -< e must now be writen as a -<< e.  The former needs only
Arrow, but a cannot use variables defined inside the proc; the latter
needs ArrowApply, but can use any variables.  There are some differences
in the less frequently used syntax for combining forms.  The next release
of the preprocessor will support the same syntax as GHC 6.2.

The GHC version also does not (yet) support case commands.