On 10/23/07, Ashley Yakeley
On Sun, 2007-10-21 at 22:04 +0200, apfelmus wrote:
Twan van Laarhoven wrote:
My proposal would be the following. The important things are that: 1. It incorporates Conal's deep arrow, 2. as well as everything that is needed for functional references/lenses and bijective/invertible functions.
I'd opt for more research for that proposal to answer the following essential questions: - Do the classes correspond to already-known categories, i.e. are the class names optimal? - What laws do we expect to hold? - Are the signatures minimal, i.e. does there exist a smaller set of combinators that still achieves the intended effect? Are the signatures complete, i.e. can the intended effect always expressed with the given combinators? - Plenty and useful examples? At least enough examples that fit in the fine grained hierarchy but cannot be fit into a coarser grained one so as to demonstrate the necessity of a fine grained hierarchy.
I tend to agree. Rather than being part of this change, it might be better for someone to work on this as a separate library, and then make a proposal to redefine the Arrow classes once it's well-understood and settled.
+1 /Josef