]> On Tue, Oct 06, 2009 at 01:38:20PM +0100, Jon Harrop wrote: > On Tuesday 06 October 2009 13:19:58 Philippe Wang wrote: > > Hello, > > > > I don't know the actual reason, but I guess it's simply a choice of > > semantics. > > > > It woud be weird to be able to deconstruct (Bar 42) while not be able > > to deconstruct (Bar) as it's not constructed. > > I mean we can write (match x with Bar y -> y). > > If partial construction were accepted we may like to write > > (match x with Bar -> x) but we couldn't because Bar is like a function > > then. > > > > With type t = A | B of int > > what would be the error warning for > > (match x with A -> 42 | B -> 43) ? > > > > Well, then I guess the reason is that it would be complicated to > > choose some sound enough semantics for partial application of > > constructors, since the solution of having to write (fun x -> Bar x) > > is much simpler. > > Can you not just say that Bar in an expression is a function (fun x -> Bar x)? This is what standard ML seems to do. Rich. -- Richard Jones Red Hat