From owner-sc22wg5@dkuug.dk Sat May 3 00:36:56 2003 Received: (from majordom@localhost) by dkuug.dk (8.12.8p1/8.9.2) id h42Mau1k085973 for sc22wg5-domo; Sat, 3 May 2003 00:36:56 +0200 (CEST) (envelope-from owner-sc22wg5@dkuug.dk) X-Authentication-Warning: ptah.dkuug.dk: majordom set sender to owner-sc22wg5@dkuug.dk using -f Received: from mailhub.dfrc.nasa.gov (mailhub.dfrc.nasa.gov [130.134.81.12]) by dkuug.dk (8.12.8p1/8.9.2) with ESMTP id h42MZREc085945 for ; Sat, 3 May 2003 00:36:52 +0200 (CEST) (envelope-from maine@altair.dfrc.nasa.gov) Received: from mail.dfrc.nasa.gov by mailhub.dfrc.nasa.gov with ESMTP for sc22wg5@dkuug.dk; Fri, 2 May 2003 15:34:03 -0700 Received: from altair.dfrc.nasa.gov ([130.134.20.211]) by mail.dfrc.nasa.gov (Post.Office MTA v3.5.3 release 223 ID# 0-71686U2500L200S0V35) with ESMTP id gov for ; Fri, 2 May 2003 15:36:13 -0700 Received: from altair.dfrc.nasa.gov (localhost.localdomain [127.0.0.1]) by altair.dfrc.nasa.gov (8.12.8/8.12.5) with ESMTP id h42MaHEc009235 for ; Fri, 2 May 2003 15:36:17 -0700 Received: (from maine@localhost) by altair.dfrc.nasa.gov (8.12.8/8.12.8/Submit) id h42MaHUb009231; Fri, 2 May 2003 15:36:17 -0700 From: Richard Maine MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-Id: <16050.62177.156544.391246@altair.dfrc.nasa.gov> Date: Fri, 2 May 2003 15:36:17 -0700 To: sc22wg5@dkuug.dk Subject: Enum has been emasculated X-Mailer: VM 7.07 under 21.4 (patch 8) "Honest Recruiter" XEmacs Lucid Sender: owner-sc22wg5@dkuug.dk Precedence: bulk Here's a paper for Dresden. I thought this one had sufficient technical content to merit a separate paper instead of throwing it in with my paper of miscellaneous comments. -- Richard Maine | Good judgment comes from experience; Richard.Maine@nasa.gov | experience comes from bad judgment. | -- Mark Twain ----------------------------------------- Date: 2 May 03 To: WG5 From: Richard Maine Subject: Enum has been emasculated In the process of removing typealias, paper j3/03-119r1 redefined enum so that it no longer depended on typealias. Unfortunately, this redefinition was done with an ax; it just deleted the part of enum that formerly referred to typealias. In my opinion, this so emasculates enum as to make it an embarrassment - it cut out the most important part of enum. Enum in the current draft is fundamentally a feature for C interop; we deleted the non-BIND(C) variant of it. As an interop feature, the fundamental point of enum is to determine the appropriate integer kind that would interoperate with the corresponding C enums....and that's the part that got cut out. What remains is just the syntactic sugar of having a different syntax for defining a set of integer named constants. Without type aliases, we need to use a kind type parameter. That would be ok, but the enumeration doesn't give us one. One can still deduce the kind, but only by using an indirection, the silliness of which just points out that the current feature design is flawed. You have to pick one of the enumerators at random and do an inquiry on it. For example, if we want to declare a variable appropriate for the enumeration given in Note 4.66 on page 65 (after it is corrected to actually conform to the bnf), we need to do something like integer, parameter :: pc_kind=kind(red) integer(pc_kind) :: some_variable or, if we had no other need for pc_kind, we could shorten it to integer(kind(red)) :: some_variable This is just silly. What is special about red here? Nothing, but we need to choose one of the enumerators at random. The enumeration should directly define a parameter for this purpose instead of requiring us deduce it by inquiring about one of the enumerators. Syntax TBD. One obvious possibility is just to put the kind parameter name in the same place as we used to have the typealias name. I suppose that in principle it could even be optional, though it seems likely to be wanted almost all the time in practice. In my opinion, if we should either fix this problem or delete enum entirely (which we voted not to do at the previous meeting). As is, it's flaws are so blatant as to be an embarassment.