- Oberon - mailman3.inf.ethz.ch

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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Re (2): Streams.
by peter＠easthope.ca 24 Apr '21

24 Apr '21

From: Charles Perkins <chuck(a)kuracali.com> Date: Thu, 22 Apr 2021 12:34:35 -0700 > I was just wishing for streams in Project Oberon so this is timely for me. Charles, can you elaborate on the motivation for Streams please. Why not just use Files directly? Can your requirements help to illustrate? Thx, ... P. -- VoIP: +1 604 670 0140 Bcc: peter at easthope. ca

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Streams.
by peter＠easthope.ca 22 Apr '21

22 Apr '21

Hi, Background Studying Oberon.Mail.Mod in ETH Oberon and use of Streams therein. I wondered about the purpose and necessity of the Streams module. Didn't find an explanation in Oberon. The comment in A2 is helpful. MODULE Streams; (** AUTHOR "pjm/be"; PURPOSE "I/O buffering and formatted writing and reading"; *) In Oberon.Mail.Mod ... PROCEDURE AddMsgHead(pos: SIGNED32); ... S := Streams.OpenFileReader(msgsF, pos); That opens the messages file, msgsF. Appears that the file is not closed before "END AddMsgHead". Is that good practice? Shouldn't msgsF be closed by the end of the procedure? Opening the msgsF at each reading of the head of a message seems inefficient. Why not open the file when the module is loaded? Then set the rider when necessary. Ref. https://svn.inf.ethz.ch/svn/lecturers/a2/trunk/source/ userid infsvnh.anonymous password anonymous TIA, ... P. -- VoIP: +1 604 670 0140 Bcc: peter at easthope. ca

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obnc can't find obnc-compile
by Duke Normandin 14 Apr '21

14 Apr '21

Could not figure out how to output real numbers in human-readable format using the vishaps compiler. So I installed obnc. From the CLI, I can run obnc, obnc-compile, etc without a problem, so there doesn't seem to be $PATH issue. However, when I try to compile my code: --> obnc tempConvert.obn sh: 1: /usr/local/bin/obnc-compile: not found obnc: build process failed It may be that I'm jinxed when it comes to using Oberon - in any flavour. :( -- Duke Normandin <dukeofpurl(a)gmx.com>

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Re: [Oberon] Simple REAL output (was: can't find obnc-compile)
by Chris Burrows 11 Apr '21

11 Apr '21

> -----Original Message----- > From: Oberon [mailto:oberon-bounces@lists.inf.ethz.ch] On Behalf Of Duke > Normandin > Sent: Saturday, 10 April 2021 11:54 PM > To: Oberon > Subject: [Oberon] obnc can't find obnc-compile > > Could not figure out how to output real numbers in human-readable format > using the vishaps compiler. So I installed obnc. > If the Oberon library you are using doesn't include a procedure to output real numbers exactly the way you want them to appear in your example it is quite feasible to do this yourself using library procedures that do exist. This would be an ideal introductory exercise for you to try. For example, follow these steps if you want to output a real number with 1 decimal place e.g. 98.6 1. Use the Oberon ENTIER function to get the whole part of the real number as an integer (= 98). 2. Subtract the result you got in (1) from the real number to get the fractional part (= 0.6). 3. Get the first digit of the fractional part by multiplying it by 10.0 (= 6.0) and use ENTIER to discard any other digits (= 6). Output the result you got in (1) using Out.Int: "98" Output the decimal point using Out.Char: "98." Output the result you got in (3) using Out.Int: "98.6" Regards, Chris Chris Burrows CFB Software https://www.astrobe.com/RISC5

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Oberon board, 2021
by Aubrey McIntosh 10 Apr '21

10 Apr '21

I have a windfall that will allow me to buy a hardware system that will support the Oberon / FPGA environment. I don't know the current status of board recommendation and such, and anyway it is a moving target. My last reasonably current status was in the Spartan board era. I would like to build some custom peripherals that are deeply coupled with my software. A representative example would be a 32-bit adder. An even more aggressive example would be a sha-256 stamper. I was somewhat active with Bitcoin long ago when a FPGA board was powerful enough for Bitcoin. I have also previously built a board with various A/D converters, with a view of using them in an undergraduate chemistry curriculum. The one restriction I can think of, I want to be able to program the hardware with homebrew and/or freeware. Previously, I have produced a board that could "in circuit program" a clone of itself. So, while not a professional, I am able to work at a level that pleases me. I think a group buy always makes sense. -- Aubrey McIntosh, PhD

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Re: [Oberon] obnc can't find obnc-compile
by Hans Klaver 10 Apr '21

10 Apr '21

Sorry, I meant to write: On 4/10/21 4:23 PM, Duke Normandin wrote: > (...) So I installed obnc. > > From the CLI, I can run obnc, obnc-compile, etc without a problem, so there doesn't seem to be $PATH issue. > > However, when I try to compile my code: > > --> obnc tempConvert.obn > sh: 1: /usr/local/bin/obnc-compile: not found > obnc: build process failed Possibly you have two separate installations of obnc. Try: $ which obnc-compile and: $ echo $PATH and notice if the path to obnc-compile is in $PATH -- Hans Klaver

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Re: [Oberon] In.Real not working
by Duke Normandin 09 Apr '21

09 Apr '21

@Dave Brown @David Lightfoot In.Open solved the problem! My petty program works a treat! [code] (* for voc compiler: voc filename.ob2 -M for obnc compiler: *) MODULE tempConvert; IMPORT In, Out; (* global variables declared here *) VAR choice:INTEGER; VAR temp:REAL; PROCEDURE fahr2cels(fahr:REAL):REAL; BEGIN RETURN 0.5556*(fahr - 32) END fahr2cels; PROCEDURE cels2fahr( cels:REAL):REAL; BEGIN RETURN cels * 1.8 + 32 END cels2fahr; BEGIN (* main program body*) choice := 0; temp := 0.0; Out.String("Temperature Conversion Utility");Out.Ln; Out.String("------------------------------");Out.Ln; Out.String("1 - Fahrenheit TO Celsius");Out.Ln; Out.String("2 - Celsius TO Fahrenheit");Out.Ln; Out.String(" - Enter your Choice");Out.Ln; In.Int(choice); CASE choice OF 1 : Out.String('Enter a number/temperature TO convert: '); In.Open; In.Real(temp); Out.Ln;Out.String("Your input was ");Out.Real(temp,3);Out.String(" Fahrenheit!");Out.Ln; Out.String("That's "); Out.Real( fahr2cels(temp),3);Out.String(" In Celsius!"); | 2 : Out.String("Enter a number/temperature TO convert: "); In.Open; In.Real(temp); Out.Ln;Out.String("Your input was ");Out.Real(temp,3);Out.String(" Celsius!");Out.Ln; Out.String("That's "); Out.Real(cels2fahr(temp),3);Out.String(" In Fahrenheit!"); ELSE Out.String("Sorry! Invalid Choice"); END; (*CASE*) Out.Ln; END tempConvert. [/code] Now I need to go and read up on how to output the temperatures in non-scientific notation. I'll find it!! Thx a bunch!! -- Duke Normandin <dukeofpurl(a)gmx.com>

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