On Mon, Jan 22, 2007 at 02:57:27PM +0000, Simon Peyton-Jones wrote:

This proposal is a very lightweight (and hence, I hope, cost-effective) proposal for a view-like mechanism.

http://hackage.haskell.org/trac/haskell-prime/wiki/ViewPatterns

This could be considered a generalization of field matching (minus the data constructor), so you'd presumably want similar syntax for the two.