April 2021 - Oberon - mailman3.inf.ethz.ch

Re: [Oberon] Emulators
by Jörg 15 Feb '22

15 Feb '22

Wojtek > How can I proceed, in practical terms, to use your JS emulator for development? Perhaps we should start discussing, WHAT you want to change. At the moment I see three different levels of HW modifications: easy, more difficult, impossible. Basically, see an emulator as virtualization. In virtualization you have a host machine (where the emulator runs on) and a guest machine (this is the FPGA board). I ignore „containers“ at the moment Easy: if you want to extend the RISC-5 instruction set in Verilog (eg add an autoincrement instruction) the modification of the emulator is rather straight forward. I neglect the fact that you have to modify the Oberon-07 compiler to use this new instruction, because this is not important for the emulator. More difficult: if you want to add IO mapped HW (eg Ethernet or Wifi) or memory mapped HW (eg color display) to your FPGA and the host machine has an equivalent of this HW, with a little bit of effort the emulator can be modified to map the IO register commands or new memory layout to the corresponding host HW. Impossible: if you want to add HW to your FPGA and the host machine does not have an equivalent HW (eg a neutrino sensor) then it‘s impossible for the emulator to mimic the new FPGA HW. br Jörg

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Wanted: Oberon Syntax in TextMate, Sublime Text or Atom Grammar
by Treutwein Bernhard 01 Jan '22

01 Jan '22

Does somebody have grammars for Oberon / Oberon-2 / Component Pascal / Active Oberon as grammar for TextMate / Sublime Text / Atom Background: Github wrongly classifies Oberon / Oberon-2 / Component Pascal / Active Oberon as Modula-2. I opened quite some tiome ago an issue in the github/linguist project (https://github.com/github/linguist/issues/3888) and they don't accept EBNF grammars. -- Bernhard Treutwein

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Re: [Oberon] _Compiler_Construction_ by Niklaus Wirth
by peter＠easthope.ca 17 Nov '21

17 Nov '21

P.s. for interest. From: peter(a)easthope.ca Date: Thu, 07 Jan 2021 08:37:22 -0800 > Currently the cheapest copy of _Compiler_Construction_ is 43.09 US$, > delivery in the USA included. Appears the copy posted at 43.09 US$ was sold that day. Subsequently the vendor listed another copy at 105.61 $US. The book market can be as volatile as the stock market. Regards, ... P. L. -- Tel: +1 604 670 0140 Bcc: peter at easthope. ca

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Usenet group comp.lang.oberon is no longer accessible
by Chris Burrows 30 May '21

30 May '21

The Usenet group 'comp.lang.oberon' which I normally access through Google Groups has recently become unavailable with the message: "Banned content warning: comp.lang.oberon has been identified as containing spam, malware, or other malicious content." https://groups.google.com/g/comp.lang.oberon While it is true that spammers occasionally attacked this group (I usually reported such attacks - maybe I shouldn't have?) there was about 30 years' worth of historically significant discussions about Oberon contained in the archived messages so it is an extreme case of 'throwing the baby out with the bathwater'. I reported the access problem to Google Groups about a week ago but haven't heard back yet. Does anybody know how to restore access to this group? If you are unfamiliar with what I'm talking about, see the similar Usenet discussion group comp.lang.modula2 which is still active and accessible: https://groups.google.com/g/comp.lang.modula2 Thanks, Chris Burrows CFB Software https://www.astrobe.com

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Re (2): Re (2): Streams.
by peter＠easthope.ca 04 May '21

04 May '21

From: Charles Perkins <chuck(a)kuracali.com> Date: Thu, 22 Apr 2021 15:31:34 -0700 > I would like to be able to chain commands, where the output of one command > is treated as the input to another command. Something like: > > Stream.Do List.File AFile.txt | Lines.Uppercase | Lines.Sort | Lines.Uniq | Lines.Count > ... OK, thanks. That gives me some perspective. I need to read Streams in Oberon and in A2 again and review use in Mail again. In the Oberon subsystem of UnixAos, I encountered a limit on the number of executions of Files.Old(). According to memory, enough executions froze the system. Appeared that the limitation came from Linux. Each execution created a temporary file until a limit was struck? That motivates my interest in the use of Files in Streams. Understanding software (or any technology) retrospectively can be a challenge. Thx, ... P. -- VoIP: +1 604 670 0140 Bcc: peter at easthope. ca

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AppleGS Orca Modula-2 Compiler
by edzard＠kolks.nl 27 Apr '21

27 Apr '21

Hello All, I know this is a Oberon mailing list but maybe a few are interested in (a good) Modula-2 compiler as well. Ken Gagne and Mike Westerfield reached out to to Peter Easdown, developer of the OCRA Modula-2 for AppleGS. Ken just e-mailed me that Peter made the source available at https://github.com/pkclsoft/ORCA-Modula-2 Best regards, Edzard

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Resetting a file rider without creating a new stream.
by peter＠easthope.ca 27 Apr '21

27 Apr '21

Hi, I'm interested to add this procedure to the Oberon Mail module. PROCEDURE WriteMsgLine(CONST no: SIGNED32); VAR len, pos: SIGNED32; h: MIME.Header; cont: MIME.Content; str: ARRAY BufLen OF CHAR; strm: Streams.Stream; BEGIN Texts.WriteString(W, "Mail.Show "); Texts.WriteInt(W, no, msgNoWidth); Texts.Write(W, " "); strm := Streams.OpenFileReader(msgsF, msgs[0].pos); strm.mode := Streams.binary; Files.Set(strm.R, msgsF, msgs[no].pos); ... END WriteMsgLine; No problem with the two lines following BEGIN. The third line is meant to reposition the rider on msgsF but it fails to compile. A FileStream extends a Stream and has rider R. A Stream does not have a rider and consequently strm.R is meaningless. A new stream with new rider can be created but changing the rider in the existing stream would be more efficient. Is there a way change the rider without creating a new stream. Thx, ... P.L. -- VoIP: +1 604 670 0140 Bcc: peter at easthope. ca

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Re (n): Resetting a file rider without creating a new stream.
by peter＠easthope.ca 25 Apr '21

25 Apr '21

From: strohm@...mail.net Date: Sun, 25 Apr 2021 08:53:00 -0400 > A Stream has certain semantics. ... it doesn't reposition ... OK, I accept that a Stream is not indexable; after a stream is created, the position on the underlying file is not available for adjustment. The Streams modules in ETH Oberon and A2O have Close procedures. I'd expect Streams.OpenFileReader() and Streams.Close() to be paired. The Mail module opens several streams; there is no Close. Disposal of obsolete streams is left to the garbage collector? If there is risk of obsolete streams occupying to much memory, I should invoke garbage collection? Thx, ... P.L. -- VoIP: +1 604 670 0140 Bcc: peter at easthope. ca

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Re (2): Resetting a file rider without creating a new stream.
by peter＠easthope.ca 25 Apr '21

25 Apr '21

From: strohm@...mail.net Date: Sat, 24 Apr 2021 00:52:13 -0400 > Assuming you're talking about Ulm's Streams module, described at > http://www.mathematik.uni-ulm.de/oberon/0.5/lib/man/Streams.html, it looks like > you want the third line to be something along the lines of: > > =C2=A0 =C2=A0 Streams.Seek(strm, msgs[no].pos, Streams.fromStart); Thanks. That makes perfect sense. ETH Oberon and the A2O here. Streams lacks a Seek procedure. One further oddity: this Oberon has the procedure name OpenFileWriter but returns a stream rather than a FileStream. (** Opens a stream writing on file F starting at postion pos. *) PROCEDURE OpenFileWriter*(F: Files.File; pos: SIGNED32): Stream; Why not make it return a FileStream rather than a Stream? That would allow changing the rider. Thx, ... P. L. -- VoIP: +1 604 670 0140 Bcc: peter at easthope. ca

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Installable file systems; was Re (n): Streams.
by peter＠easthope.ca 24 Apr '21

24 Apr '21

From: Joerg <joerg.straube@ia....ch> Date: Fri, 23 Apr 2021 05:26:32 +0200 > The main drawback of the ProjectOberon system as of today is that Files.Mod i= > s directly bound to the implementation of the Oberon file system and is not o= > nly a dispatcher with PROCEDURE variables. > ... easily=E2=80=9C bind another file system t= > o the Files interface and all modules using Files can benefit of this new im= > plementation, even the Oberon system itself. Hello Joerg, My knowledge is superficial but your explanation reminds of Section 6.1.1, page 100, in the Ph.D. thesis of Pieter Muller. http://e-collection.ethbib.ethz.ch/ecol-pool/diss/fulltext/eth14755.pdf "In Native Oberon, there was a need to allow many kinds of file system for interoperability with other operating systems installed on the same machine, to access several kinds of removable media with their own file system formats, and to access file systems located on remote servers. The installable file system framework developed for Native Oberon ..." Put an updated ETH Oberon on a Skulski machine? Regards, ... P. L. -- VoIP: +1 604 670 0140 Bcc: peter at easthope. ca

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