February 2007 - Oberon - mailman3.inf.ethz.ch

RE: [Oberon] New BB release
by Easthope 07 Feb '07

07 Feb '07

Oberon & Aos users, Sorry if you find this arcane. As I see, Dialer.Mod was designed to operate a modem for establishing a PPP connection. Recently I purchased a long distance telephone calling card and wonder about also using Dialer to establish a call. This would save me from dialing the access numbers for the calling card and would also allow invocation from my Desktop.Tool. Along with all its other uses, the Desktop.Tool would be a telephone directory! So perhaps modems are not quite obsolete. This is my idea of generalizing the command syntax. If anyone can offer a suggestion or criticism it will help. Extant syntax is Dialer.Dial <config> <device> ~ For example "Dialer.Dial carnot Device0 ~". First I wonder about the benefit of the device being a parameter of the command rather than being in the Oberon.Text. For example, config.Init might be Init = { Device0 COM1 19200 }

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New BB release
by Ulrike Glavitsch 07 Feb '07

07 Feb '07

Dear BB users, a new crazy-fresh release is available under http://www.bluebottle.ethz.ch/dlcrazy.html for download. It mainly contains bug fixes and cleanups. However, for developers using PET there is a significant change. The compiler option \Ws is set per default. This means that all unused constants, variables, types, procedures and modules are marked when you compile source code from PET. This may help to keep your code clean from unused code. Compiler warnings are denoted with a yellow marker whereas compiler errors continue to be marked in red. I wish everyone good luck with the new release. Best regards, Ulla Glavitsch -- ETH Zürich Ulrike Glavitsch Eggler Institut für Computersysteme Clausiusstrasse 59 CH-8092 Zürich Tel.: +41 44 632 70 49 Fax : +41 44 632 13 07

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literal value for end of line character?
by Eric 05 Feb '07

05 Feb '07

Hi all, I wish to test a character to see if it is equal to the end-of line character. (In Java this would be c == '\n'). How does one do this in Oberon? I tried ch = DX where D is the hexadecimal value for carriage return, but I got a compiler error. E.

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Re: N-O Scanner structure confusing ?
by Chris Glur 04 Feb '07

04 Feb '07

On 1 Feb 2007, Chris Glur <easlab(a)absamail.co.za> wrote: > > Lets examine how we could possibly process text after the very versatile > > scanner has found a searched-for token. > > ... Thomas wrote: > Texts.Scan is designed for scanning command parameters. > It's also used as you mention for OberonErrors.Text > which is formatted to allow with ease Texts.Read following Texts.Scan. > These texts have no delimiters between tokens but canonical ones like > space, tab, cr > and arbitrary single characters are escaped by "\". > Some other texts need workarounds or their own scanners. > > hoping that could be of some help, It helps to confirm that I'm increasingly having difficulties to explain. The Scanner is well designed for any Algol60-family-lang compiler. Ie. where the tokens are demarcated by white-chars. Apparently python has syntactic-info in the text-indentations ? Scanning command parameters is just a bonus. Here's a simple job which I can't acheive -- directly yet. 1. set the caret 2. scan from the caret until the token "END" 3. reset the caret after the found token. The problem is that I don't know how to get the char-position where the token was found, other than by an absurd method of counting the <CRs> which the scanner saw and then using the reader to read the whole text-stretch which the scanner has already proccessed. Besides, the scanner has obviously used the reader to do the job. Thanks, == Chris Glur.

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Parallel computing ?
by Chris Glur 03 Feb '07

03 Feb '07

Brantley Coile wrote: > http://www.eecs.berkeley.edu/Pubs/TechRpts/2006/EECS-2006-1.html > > >> "In an InformationWeek article entitled 'Where's the Software to Catch >> Up to Multicore Computing?' the Chief Architect at IBM gives some fairly >> compelling reasons why your favorite software will soon be rendered >> deadly slow because of new hardware architectures. Software, she says, >> just doesn't understand how to do work in parallel to take advantage of >> 16, 64, 128 cores on new processors. Intel just stated in an SD Times >> article that 100% of its server processors will be multicore by end of >> 2007. We will never, ever return to single processor computers. >> Architect Catherine Crawford goes on to discuss some of the ways >> developers can harness the 'tiny supercomputers' we'll all have soon, >> and some of the applications we can apply this brute force to." >> -- Doug Danforth wrote: > Random Access Memory (RAM) is fast because it is massively parallel. A > 32 bit address is broadcast simultaneously to all locations in memory > and only one of those addresses responds by placing its contents on the > output bus (read operation) or by modifying its contents from the input bus (write operation). Perhaps 'associative memory' works something like that, but standard RAM has very little parallelism. Except for the 32 'select left or right channels' which are simultaneously set. Then serially, ie. AFTER the 32 'railway points' are all set, the train travels serially [at the speed of light] to the destination. Ie. it has to pass switch n before it passes switch n+1. The only parallelism comes from the 32 bit adr-bus, which sets all 'railway points' together. Which is no different from the centuries old punch-card fabric weavers. But that's only possible because the 32 bits were already setup and stored BEFORE, which was inevitably determined serially. Ie. if you are going to get the byte at adr. A, this decision has already been determined by the compiler - serially. The adr. A is determined before and stored for later use. The first bloke who made a printing press, printed all the letters of the page in parallel, but he needed a week to carve the wood. And remember that 20 yes/no questions will select 1 from out of a million. > What does this have to do with computing? It is the next level for it > is a pattern matching and completion machine. Presented with an image > of a fuzzy "O" it is possible to clean it up and retrieve a very good > representation of an O (actual experiment performed). It can do face > recognition, speech recognition, weather prediction, handwriting > recognition, and other pattern matching tasks. I expect great results from tasks that can run in parallel and am waiting for Hoare's transputer to come back once WinTel tops out. The idea of a network of heuritic collaborators, where it's not necessay to really know exactly what's happening works for the internet. For oberon-types, I think the next wave is mobile. So ARM should shine. I thought Oberon-ARM was just Wirth's hobby helicopter project. But I read that ETH was 2nd behind MIT in a very serious engineering project competition. In 1945 the atom bomb was the top weapon/defence, then the H-bomb, then stealth missiles. With today's situation unmanned aircraft are appropriate. So ETH is at the leading edge of advanced weaponry. Until biological sciences make our hard technology irrelevant. == Chris Glur.

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N-O Scanner structure confusing ?
by Chris Glur 02 Feb '07

02 Feb '07

Lets examine how we could possibly process text after the very versatile scanner has found a searched-for token. The Scanner is initialised by: OpenScanner* (VAR S: Scanner; T: Text; pos: LONGINT); (** Open text scanner S and set it up at position pos in text T. *) But there seems no good reason to have the 'pos' arg a VAR-par, since it seems not to be changed ? PROCEDURE Scan* (VAR S: Scanner); uses the Record Reader, which allows access to its 'position' via the function-proc 'Pos'. Ie. PROCEDURE Pos (VAR R: Reader): LONGINT; (* Return reader's position within the text. *) Again, why is this paramenter/arg 'Reader' a VAR-par ? The 2 stepped fields of Reader : bufpos, off are private and inaccessible. The fact that Scanners are descendants of Reader records, also doesn't directly allow up-casting to allow using the Reader's 'Pos' function-proc. AFIAK ? Obviously the compiler uses the Scanner directly to work with tokens, ie. not characters; and then indicates character positions, eg. with the "error message". Previously in order to delete various fields from NewsMessages, I've used the powerfull scanner to locate the fields, while using it's 'count CRs facility". And then a re-read with the Reader using the counted CRs to get the final char-positions to do the deleting. That's an adsurd method ! It's time to know how the character position of the Scanner is directly found. Since the scanner uses 1-char-look-ahead to show the next char, why can't it also tell the position of this char ?! Thanks for any input, == Chris Glur.

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format of source.arc
by Brantley Coile 01 Feb '07

01 Feb '07

Can someone send me the module to pull apart the .arc files for the Native Oberon?

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