Squeak-dev January 2000

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131 participants
468 discussions

Re: FreeType plugin, was Re: [ENH] DES with Plugin
by Henrik Gedenryd 28 Jan '00

28 Jan '00

Duane Maxwell wrote: > Nice try. > Yes, and in the future I'll also try not to make a fool of myself in public by forgetting to set the right return address. Oh well, luckily it wasn't too bad. Apologies to everyone. Henrik < = > .

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Re: Type Safety (was Re: fun and empowerment)
by garau＠ar.ibm.com 28 Jan '00

28 Jan '00

| Mark Guzdial wrote: | Does anyone know of any empirical evidence for the value | of types? Or is it a myth that we invented to rationalize the typing | needed to improve the compiler's performance? I think that, as with many others, the word 'type' (and related concepts 'type checking', 'type safe', 'strong typing', etc.) are somewhat abused. I believe Smith and Ungar when the say in "Programming as an Experience: The inspiration of Self" (section 2.1) that types were invented in order to help the programmer generate correct code. Then this same information was used to communicate design intention to humans. (I attach these paragraphs at the bottom of this note) So, the first thing to make clear is: Who are the types intended for? - If the reader will be a human, we need the most general and abstract kind of types (ie set of messages to be understood). - If the reader will be a compiler, the most detailed and precise information is needed. Ole Agesen calls them "Concrete Type", and it is basically the class of an object. It would be nice that this information could be deduced automatically, and that is (Concrete) Type Inference. I and some other guys at MathMorphs have been caught by this fascinating area. As a result of that research, I am writing the final work (like a thesis) to get my graduation in Computer Science. (The code is available at http://typeinference.swiki.net). One of the main differences with Ole's work is that we consider not only the class but also the instance variables when defining the (concrete) type of an object. Now, the fragment from "Programming as an Experience" Type Declarations. In order to understand the design of the Self language it helps to examine the assumptions that underlie language design. In the beginning, there were FORTRAN, ALGOL and Lisp. In all three of these languages the programmer only has to say what is necessary to execute programs. Since Lisp was interpreted, no type infor mation was supplied at all. Since ALGOL and FORTRAN were compiled, it was nec essary for programmers to specify primitive type information, such as whether a vari able contained an integer or a float, in order for the compiler to generate the correct in structions. As compiled languages evolved, it was discovered that by adding more static declarations, the compiler could sometimes create more efficient code. For example, in PL/I procedures had to be explicitly declared to be recursive, so that the compiler could use a faster procedure prologue for the nonrecursive ones. Programmers noticed that this static declarative information could be of great value in making a program more understandable. Until then, the main benefit of declarations had been to the compiler, but with Simula 1 and PASCAL a movement was born; using dec larations both to benefit human readers and compilers. In our opinion, this trend has been a mixed blessing, especially where objectoriented languages are concerned. The problem is that the information a human needs to under stand a program, or to reason about its correctness, is not necessarily the same informa tion that a compiler needs to make a program run efficiently. But most languages with declarations confuse these two issues, either limiting the efficiency gained from decla rations, or, more frequently hindering code reuse to such an extent that algorithms get duplicated and type systems subverted. Francisco (Pancho) Garau Ph: (5411) 4319-6213. Fax: (5411) 4319-6422 garau(a)ar.ibm.com (work) - - - fgarau(a)bigfoot.com (home)

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Re: xml.smalltalk.org and mod.smalltalk.org
by Peter William Lount 28 Jan '00

28 Jan '00

Hi Randal, Thanks. I've added those links to the web site and quoted you... ;--). While it is important to consider other standards especially if they are popular it's also important to make sure that the XML Smalltalk format doesn't compromise any smalltalk related requirements. XML is great for the exact reason that it's extensible. Peter William Lount peter(a)smalltalk.org http://xml.smalltalk.org ---------- From: Randal L. Schwartz <merlyn(a)stonehenge.com> To: Peter William Lount <peter(a)smalltalk.org> Cc: Squeak Mail List <squeak(a)cs.uiuc.edu> Subject: Re: xml.smalltalk.org and mod.smalltalk.org Date: January 28, 2000 12:50 PM >>>>> "Peter" == Peter William Lount <peter(a)smalltalk.org> writes: Peter> I think it's important that we have a "XML" ASCII standard for Peter> storing BOTH "Smalltalk source code" and "Smalltalk object Peter> instances". Interoperatability is becoming very important and Peter> being able to share object instances with other languages and Peter> systems would revolutionize the Smalltalk usage in the real Peter> world. If you want an XML marshalling for objects, it'd be great to be compatible with either the WDDX standard, or the SOAP standard, as much as possible. Unfortunately, both seem to have big backers (SOAP from M$, and WDDX from Allaire), and are incompatible. SOAP seems to have derived from the XML-RPC camp, which also has more visibility. SOAP is at http://www.develop.com/soap/ WDDX is at http://www.wddx.org/ Peter> In addition I think it's important that there be an Apache Web Peter> Server module for Smalltalk. A ModSmalltalk. Any computer Peter> language that tightly intergrates and interoperates with the Peter> Apache Web server in an Open Source manner can gain prominance Peter> in the Web Site and Web Applications Market. Smalltalk has an Peter> excellent potential to be the engine behind many powerful, yet Peter> to be built, web sites. Oooh oooh! -- Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095 <merlyn(a)stonehenge.com> <URL:http://www.stonehenge.com/merlyn/> Perl/Unix/security consulting, Technical writing, Comedy, etc. etc. See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl training!

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Re: xml.smalltalk.org and mod.smalltalk.org
by merlyn＠stonehenge.com 28 Jan '00

28 Jan '00

>>>>> "Peter" == Peter William Lount <peter(a)smalltalk.org> writes: Peter> I think it's important that we have a "XML" ASCII standard for Peter> storing BOTH "Smalltalk source code" and "Smalltalk object Peter> instances". Interoperatability is becoming very important and Peter> being able to share object instances with other languages and Peter> systems would revolutionize the Smalltalk usage in the real Peter> world. If you want an XML marshalling for objects, it'd be great to be compatible with either the WDDX standard, or the SOAP standard, as much as possible. Unfortunately, both seem to have big backers (SOAP from M$, and WDDX from Allaire), and are incompatible. SOAP seems to have derived from the XML-RPC camp, which also has more visibility. SOAP is at http://www.develop.com/soap/ WDDX is at http://www.wddx.org/ Peter> In addition I think it's important that there be an Apache Web Peter> Server module for Smalltalk. A ModSmalltalk. Any computer Peter> language that tightly intergrates and interoperates with the Peter> Apache Web server in an Open Source manner can gain prominance Peter> in the Web Site and Web Applications Market. Smalltalk has an Peter> excellent potential to be the engine behind many powerful, yet Peter> to be built, web sites. Oooh oooh! -- Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095 <merlyn(a)stonehenge.com> <URL:http://www.stonehenge.com/merlyn/> Perl/Unix/security consulting, Technical writing, Comedy, etc. etc. See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl training!

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xml.smalltalk.org and mod.smalltalk.org
by Peter William Lount 28 Jan '00

28 Jan '00

Hi, I think it's important that we have a "XML" ASCII standard for storing BOTH "Smalltalk source code" and "Smalltalk object instances". Interoperatability is becoming very important and being able to share object instances with other languages and systems would revolutionize the Smalltalk usage in the real world. In addition I think it's important that there be an Apache Web Server module for Smalltalk. A ModSmalltalk. Any computer language that tightly intergrates and interoperates with the Apache Web server in an Open Source manner can gain prominance in the Web Site and Web Applications Market. Smalltalk has an excellent potential to be the engine behind many powerful, yet to be built, web sites. Please see http://xml.smalltalk.org and http://mod.smalltalk.org for more of this discussion... All the best, Peter William Lount peter(a)smalltalk.org http://www.smalltalk.org http://mod.smalltalk.org http://xml.smalltalk.org Smalltalk.org is powered by http://www.zoku.net.

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RE: Type Safety (was Re: fun and empowerment)
by Jarvis, Robert P. (Contingent) 28 Jan '00

28 Jan '00

> -----Original Message----- > From: Mark Guzdial [SMTP:guzdial@cc.gatech.edu] > Sent: Friday, January 28, 2000 8:59 AM > To: squeak(a)cs.uiuc.edu > Subject: Re: Type Safety (was Re: fun and empowerment) > > > > Does anyone know of any empirical evidence for the value > > > of types? > > > Or is it a myth that we invented to rationalize the typing > > > needed to improve the compiler's performance? > > > >Peter Norvig's book "Paradigms of Artificial Intelligence Programming: > Case > >Studies in Common Lisp", 1992, Morgan Kaufman Publishers Inc. comes out > >strongly in favour of type-declarations, citing a case on page 318 where > >various hints to the compiler give a 40x speedup, so I see no need to > >rationalize. > > I do believe that types lead to better compiler output -- I agree, no > need to rationalize that. The "value" that I'm questioning is that > types lead to more bug-free code, that types "catch errors at compile > time." That claim seems untested yet, and I'm not even sure where it > came from. Is it a rationalization, e.g., "Well, we have to have > types to make the code better -- let's claim that it's good for the > programmer to use types! Improves their thinking, let's say!" Well, > maybe... > I thought the findings in Prechelt and Tichy's paper (http://wwwipd.ira.uka.de/~prechelt/Biblio/tcheck_tse98.ps.gz) were interesting, and I think it would be useful to see this sort of study done with Smalltalk as the language instead of C. (Summary: Prechelt and Tichy found that programmers made fewer parameter type errors with ANSI C than with K&R C when working with the Motif libs). This would, of course, require the development of a compile-time typing system for Smalltalk. Sounds like something that could keep a couple of your students busy for a couple semesters, Mark. :-) Bob Jarvis Compuware @ Timken

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[ENH] DES with Plugin
by Duane Maxwell 28 Jan '00

28 Jan '00

Change Set: DES Date: 26 January 2000 Author: Duane Maxwell This class implements the Data Encryption Standard (DES) block cipher per ANSI X3.92. It requires the presence of the 'DESPlugin'. At some future date the functionality of the plugin may be provided in pure Smalltalk, but the slowness would be prohibitive for anything other than trivial usage. The main barrier to translation is the heavy use of zero-based indexing of arrays. How to use: you first provide an 8-byte key which will be used to encode and decode the data. Internally, this is 'cooked' into a 32-word format to speed up the encryption process. The data is then sent in 8-byte packets to be encoded or decoded. You must externally account for padding. See the 'testing' category on the class side for examples. As of this date (1/26/2000), the U.S. Government has lifted many of the previous restrictions on the export of encryption software, but you should check before exporting anything including this code. Macintosh plugin included.

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Squeak and Native Widget support
by Piero Campanelli 28 Jan '00

28 Jan '00

Hi. i have seen some screenshoot of changing widgets of Squeak in a way to resemble to Windows, to OS2 or any other theme. Could you point me some how-to link ? Thank you in advance Bye

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Re: Problems downloading Mark's zipped BookMorph files through a port
by Mayuresh A Kathe 28 Jan '00

28 Jan '00

Probably there is a timeout on your proxy server. Please check. Bye. -- Mayuresh A Kathe Think Different. Think Better. mayuresh(a)vsnl.com ---------- >From: Stewart MacLean <stewart.maclean(a)nzhis.govt.nz> >To: "'squeak(a)cs.uiuc.edu'" <squeak(a)cs.uiuc.edu> >Subject: Problems downloading Mark's zipped BookMorph files through a port >Date: Fri, Jan 28, 2000, 9:26 AM > > Mark, (and anybody else who might help) > > After consulting with out support chap here he pointed out that downloading > using: > > http://coweb.cc.gatech.edu/cs2340/uploads > > works as expected, whereas: > > http://coweb.cc.gatech.edu:8888/cs2340/uploads/ch1-history.zip > > times out. > > He noted that this address goes through a port :8888. > > I'm wondering why this works at home on my PC, but not here through the LAN > etc? > > Thanks, > > Stewart > >

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Re: dynabook, crusoe, and Squeak.
by Mayuresh A Kathe 28 Jan '00

28 Jan '00

Absolutely true. -- Mayuresh A Kathe Think Different. Think Better. mayuresh(a)vsnl.com ---------- >From: Blacktooth <bt(a)whitestar.soark.net> >To: squeak(a)cs.uiuc.edu >Subject: Re: dynabook, crusoe, and Squeak. >Date: Fri, Jan 28, 2000, 3:13 PM > >> You're not the only one who would have loved the original PARC attitude to >> still exist somewhere. >> >> Henrik > > > I haven't been reading all the mail, but this is my favorite quote of > the ones I have read. > > > R. Shiflett > >

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