I had not thought of this record syntax. But it does not perform the currying effect shown in the example; it just drops the omitted fields. Brandon Allbery wrote:

On Mon, Nov 5, 2012 at 4:15 PM, Stephen Tetley wrote:

...

There is a long extant GHC extension to elide constructor arguments

f (Leaf {}) = ...

...

f (Node {}) = ...

I don't think that's an extension, it falls out directly from how Haskell builds records on top of ADTs and is specified in the standard as such. See http://www.haskell.org/onlinereport/decls.html at the end of the "Labelled Fields" section for Haskell98, or the middle of section 3.15.2 in http://www.haskell.org/onlinereport/haskell2010/haskellch3.html#x8-490003.15... the H'2010 version.

-- brandon s allbery kf8nh sine nomine associates allbery.b@gmail.com ballbery@sinenomine.net unix/linux, openafs, kerberos, infrastructure http://sinenomine.net