June 2017 - Oberon - mailman3.inf.ethz.ch

FPGA Oberon - Definition Module Tool
by thomas.kral＠email.cz 08 Oct '18

08 Oct '18

Hi, I am thinking of a simple tool that could extract definition info from *.Mod and produce respective *.Def file. Definition files can be quickly looked at, to remind a programmer of the interface *.Mod modules export. While on Linux one could use grep $ grep PROCEDURE\ * *.Mod.txt to obtain info at least about procedures, but how about exported types and variables? I am looking for a recommended way how to simply code such a tool, is it a good idea to use `ORP' parser somehow for the task? I prefer to code it simple, does not have to be perfect, but should carry the idea. Tomas

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FPGA - Save / Restore OBERON.FS
by Andreas Pirklbauer 22 Jul '17

22 Jul '17

There will be an enhanced Oberon file system in Experimental Oberon offering, amongst other things, larger file sizes.________________________________________ > From: Skulski, Wojciech skulski at pas.rochester.edu > Sent: Thu Apr 20 06:42:54 CEST 2017 > My biggest concern about Oeron FS is its limited size. > Wojtek

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pcreceive.sh not working for files that are multiples of 255
by Andreas Pirklbauer 03 Jul '17

03 Jul '17

When using the Oberon emulator on a host system (e.g., Mac), the command ./pcreceive filename does not seem to work for files whose file size is a multiple of 255. Has anyone else noticed this issue? It looks like either pclink.c in the emulator or PCLink.Mod on the Oberon system needs to be corrected.

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Help: Display Init Strings for Native Oberon
by Treutwein Bernhard 03 Jul '17

03 Jul '17

Does anybody remember how to create display Init Strings for Native Oberon? Background: I recently dumped my old CRT and replaced it with a TFT, my old NO installation switches the S3 Trio display via an Init string to 90 Hz refresh Rate, which the TFT does not understand. Although I remember, how to set the boot variables temprarily (see also: http://www.ethoberon.ethz.ch/native/WebConfig.html) I do not remember how to create these crude Init strings. regards -- Bernhard

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Re: [Oberon] LONGINT, RETURN & etc. (Chris Burrows)
by Артур Ефимов 01 Jul '17

01 Jul '17

> "Single-character strings can also be assigned to variables of type CHAR." Yes, I thought about that, but only after I had sent the message. A single character string can be returned, as it may be interpreted as a character literal. Oberon 2 isn't different to other versions of Oberon in this sense. >From the syntax point of view, single-character string literals and character literals look the same in Oberon. One and the same expression "A" can be interpreted in two different ways by the compiler. (* "A" is interpreted as ARRAY OF CHAR *) VAR s: ARRAY 10 OF CHAR; BEGIN COPY("A", s) (* or s := "A" in Oberon-07 *) (* "A" is interpreted as CHAR *) VAR ch: CHAR; BEGIN ch := "A" This is not a problem, as the compiler handles this with a simple IF statement (something like "IF (char expected) & (type = string) & (length = 1) THEN type := char END"). This may be more tricky in case of constants: CONST x = "A"; There is nothing about this in the language report; however, Oberon compilers handle these situations very well. Arthur Efimov

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Re (2): LONGINT, RETURN & etc.
by peter＠easthope.ca 30 Jun '17

30 Jun '17

From: Chris Burrows <chris(a)cfbsoftware.com> Date: Sat, 17 Jun 2017 13:55:16 +0930 > http://www.astrobe.com/OberonSyntax/html/OberonSyntax.htm Date: Sat, 17 Jun 2017 13:40:15 +0930 > What you can't have is just RETURN without an expression. According to your diagrams an expression can be factor and a factor can be NIL or " ". So "RETURN END" is OK. Interesting edge case! From: =?utf-8?B?SsO2cmc=?= <joerg.straube(a)iaeth.ch> Date: Sat, 17 Jun 2017 07:08:41 +0200 statement = ... | "RETURN" [ expression] ]. Square brackets permit zero or one occurance. So the diagram and Joerg's EBNF are almost equivalent. For strict equivalence add an arrow bypassing the expression after RETURN in the diagram. Or remove the square brackets around expression. The 2nd possibility is the simplest and an empty expession is OK. statement = ... | "RETURN" expression ]. Regards, ... Lyall E. -- 123456789 123456789 123456789 123456789 123456789 123456789 123456789 Tel: +1 360 639 0202 Pender Is.: +1 250 629 3757 http://easthope.ca/Peter.html Bcc: peter at easthope. ca

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Safe module unloading
by Andreas Pirklbauer 30 Jun '17

30 Jun '17

The solution to implement "completely safe module unloading" in the Oberon system has evolved somewhat since the last entry on this topic sometimes last year. I have been asked to make a comment about the changes made since then. The updated implementation is contained entirely in two modules (Kernel, Modules) at https://github.com/andreaspirklbauer/Oberon-experimental, plus some tool commands in module System. A PDF doc explains the new implementation. The implementation cost is as follows: ca 20 additional lines in module Kernel, and ca 200 additional lines in module Modules. Best regards.Andreas

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LONGINT, RETURN & etc.
by Артур Ефимов 30 Jun '17

30 Jun '17

> RETURN " " END is valid This is not valid, because in Oberon, a functional procedure can not have ARRAY OF CHAR as return type (nor can it return a RECORD). The valid return types are INTEGER, REAL, CHAR, BOOLEAN, SET, POINTER TO ... "RETURN END" is not a valid construct in an Oberon program not because of the because of the syntax rules, but because of the semantic rules. To show the difference, consider this statement: IF '5' < 10 THEN END. This is an absolutely valid statement syntaxically, but it is not valid because of the type mismatch (you can't compare expression of type CHAR to an expression of type INTEGER). > LOOP would be a more generic way iso using REPEAT and/or WHILE. LOOP can not replace REPEAT and/or WHILE. LOOP + IF can, but not LOOP by itself. If you want to make the Oberon compiler restrict programmers to only use IF ... THEN EXIT END statement in the beginning or in the end of the LOOP statement, and only once, then the source code of the compiler will get a lot more complex, as this would no more be a syntax rule, but a semantic rule. Kind regards, Artur Efimov

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What am I missing?
by eas lab 30 Jun '17

30 Jun '17

How do *YOU* find the important info that you read in one of your files after event 17 months and before event 14 months ago? Why did 90's NativeOberon which had a single file-space and COULD do non-trivial projects, have no <list by recentcy> facility? Do other users, having worked in the single file-space for 24 months and having accumulated 7'395 files not prefer to have the most recent-files listed first? If you are making coffee, using 9 items via several repeated accesses: do you want the 9 items <on the top of the stack> until the task is completed; or do you want to repeatedly access each via it's <exactly. specified identifier> from amongst 7'395 items? I want to relate this to functional programming.

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Re (2): Oberon Wikibook.
by peter＠easthope.ca 22 Jun '17

22 Jun '17

From: Liam Proven <lproven(a)gmail.com> > A URL would have been helpful, you know... Thanks Liam. https://en.wikibooks.org/wiki/Oberon It can be read in ETHO PC Native via loband. Desktops.OpenDoc "http://www.loband.org/loband/filter/org/wikibooks/en/ /wiki/Oberon" Google of "oberon wikibook" also yields it as first link. Also, being a public wiki, a potential contributor should be aware than anything contributed might be edited in short order. Anyone sensitive about seeing his or her words changed can be happier commenting in the talk pages than editing the primary pages. Same in Wikipedia. Nevertheless the article there has developed nicely with minimal or no bickering. With any luck, the book will fare as well. Thanks again, ... Lyall E. -- 123456789 123456789 123456789 123456789 123456789 123456789 123456789 Tel: +1 360 639 0202 Pender Is.: +1 250 629 3757 http://easthope.ca/Peter.html Bcc: peter at easthope. ca

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