On Wednesday 24 August 2011, 20:24:14, Armando Blancas wrote:
Studying the paper *A Simple Implementation for Priority Search Queues*, by Ralf Hinze, I came across the following syntax that I didn't understand and I couldn't use in GHCi 7.0.3 for defining a binding data type (page 3):
Bindings are represented by the following data type: *data k -> p = k -> p* key :: (k -> p) -> k key (k -> p) = k prio :: (k -> p) -> p prio (k -> p) = p Note that we use '->' both as a type constructor and value constructor. [...] data PSQ k p
The following page has these value constructors:
*0 :: PSQ k p* *{.} :: (k -> p) -> PSQ k p*
The paper says that's Haskell '98 code.
I didn't see that claim in the linked slides, and it's not Haskell '98 (nor Haskell 2010). There's a translation of the principles to Haskell from page 17 on or so.
I'll appreciate info on what kind of data declaration those are and any pointers to related documentation. Or maybe those are deprecated features.
I don't think the notation from the beginning ever was legal Haskell, I think it was chosen to present the ideas separated from syntax.
I'm stuck in this part.
-armando
www.cs.ox.ac.uk/people/ralf.hinze/talks/ICFP01.pdf