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Subject: NY/SIGAPL Meeting Thur 9/17/98: David E. Siegel, "Namespaces in APL+WIN: A Proposal" Date: Tue, 8 Sep 1998 09:37:36 -0400 SEPTEMBER MEETING ANNOUNCEMENT of NY/SIGAPL, the New York City Area chapter of SIGAPL (the ACM Special Interest Group on APL) Title of Talk: Namespaces in APL+WIN: A Proposal Speaker: David E. Siegel Thursday, September 17, 1998 at Philips Electronics North America 1251 Avenue of the Americas, 20th Floor New York, NY between 49th and 50th Executive Council Meeting, 5:30 PM; Talk, 6:30 PM CoSyNOTES Meeting fee: NY/SIGAPL member, $5; non-member $10 Before David's presentation, we'll review the recent APL98 conference in Rome and discuss plans for the APL99 conference, to be held in Scranton, Pa. next summer, August 10-14, 1999. _______________ David will discuss the purposes of a "namespace" feature and how it should be designed both to serve the various interests of APL users and to encourage good programming practice. Namespaces have been implemented in some APL dialects, to reduce name scope and avoid name conflicts. Other implementations, including APL+WIN, do not currently support such a feature. David will describe his unofficial and preliminary proposal for the design and implementation of such a feature. Topics to be discussed include: . Purposes of namespaces . General principles . Where code runs . Visibility of objects, and changing the current namespace . Organization of namespaces within the workspace . Development tools David will present a detailed scheme for implementing these principles and will discuss differences between this scheme and existing implementations. Issues of available facilities and how they would function will be discussed, as will issues of notation. Topics in this part of David's presentation will include: . Terminology . Syntax of namespace names and references . Namespace attributes . Manipulating namespaces and their contents . A namespace search path (pro & con) . Namespaces as arguments to existing system commands and functions . Stack Considerations (quadSI) . Namespaces and system variables. In line with the principles discussed, features will be omitted or restricted that David believes are likely to introduce ambiguities or other problems or are too conducive to poor coding or design practice, compared to their benefits. David considers the design he proposes to be an improvement on those already implemented. He hopes that his proposal will stimulate discussion, which might lead to an improved design and implementation of namespaces, both in APL+WIN and in other APLs. David provides the following disclaimer: The proposal to be discussed represents his personal opinions. Although David is employed by LEX2000 Inc., owner of APL2000 Inc., he is not a part of the APL+ language design team. His proposal does not represent official policy of APL2000 Inc. He does not know when, or if, APL2000 will implement namespaces, nor in what form they might be implemented, should that occur. For any official statements from APL2000 Inc., see their web site at www.apl2000.com, send email to firstname.lastname@example.org, or write to APL2000 Inc., Two Independence Way Suite 100, Princeton NJ 08540. David Siegel may be reached by email at email@example.com, or by mail at the address above. ============================: THU.SEP,980917 :============================ |18:49| DaveSiegal abt APL99 | EdShaw OpenGL for Dyalog APL interface : ~ 150 low level interface fns to SiliconGraphics Graphics API . by AleseiZalivine , student of AlexanderSkomorokhov . $150 donation to Russian Student fund . |19:2| Name spaces . Aid encapsulation . Entities : Objects . Automatically change to name space by running . Space°Fn . vs inner product f.g . | N1 NW N3.N4 N5 | Ambiguous ° is compose in Dyalog . Dyalog uses '.' . 2 exceptions : error handler needs to run in callers space . Locality attribute with System command to ELX is treated very much like a Call . In Dyalog have ĽCS to change to calling space . Acccess attribute : Public or private . Default private . )PUBLIC LIST /LocalList and )PUBLIC space°list /RemoteList )PUBLICS | ĽAT returns attirbutes including public/private . ĽPUBLICS 'SPACE°Pattern' | 1 ĽPUBLICS 'SP°FN' |>| HeaderLine . EdShaw : Any attempt to keep compatible w Dyalog ? Implementers Rutiser & others . cc EricBaelen . Namespace SearchPath | Session vs WS variable - not thought abt for yrs. Noot NS : # . Wants to remove ĽCS . pernisious - enourage § | NS § NS.ĽFX , must be composed , sometimes need space around ' . ' , sometimes not . Create , destroy & populate NSs : )MakeSpace Space | have Ľ command in Dyalog . )MS #°FooĹGoo )COPY Foo ° A B C )NSAVE WS NS | To save NameSpace as own WS . _______________ NEXT MONTH'S NY/SIGAPL MEETING Thursday, October 22, 1998: Title of Talk: New Features in Dyalog APL/W Speaker: Peter Donnelly, Director, Dyadic Systems Limited Peter Donnelly will describe and demonstrate the major new features of Dyalog APL/W Version 8.2, which will ship during the fourth quarter of 1998. Multithreading allows you to execute more than one APL function (or indeed any expression) at the same time. This allows you to perform background processing, such as printing, database retrieval, database update, calculations, and so forth while at the same time performing other interactive tasks. The new ActiveXControl object allows you to package a Dyalog APL application as an ActiveX Control that may be included in a program written in Microsoft Visual Basic, Microsoft Excel, Borland Delphi, or in any other host application that supports ActiveX. Your Dyalog APL application can also be run inside a web page with any web browser that supports ActiveX. Other enhancements to be described include: additional APL2 language features, the :With control structure, additional GUI-related objects and support, and a Web server workspace. For more information about Dyalog APL/W Version 8.2, visit Dyadic's Web site, www.dyadic.com or contact Beautiful Systems Inc., 308 Old York Road Suite 5, Jenkintown, PA 19046 (215-886-2636, fax -4888). _______________ To obtain a free sample copy of the September issue of the NY/SIGAPL newsletter, Big Apple APL, email your request to firstname.lastname@example.org NOTE: CURRENTLY AVAILABLE ONLY BY REGULAR MAIL, OR BY FAX --For delivery by mail, please be sure to include your FULL postal address. --For delivery by fax (USA and Canada only, please), include your fax number.