[Oberon] LOOP conversion

Chris Burrows chris at cfbsoftware.com
Thu Jan 7 10:10:39 CET 2021

> -----Original Message-----
> From: Skulski, Wojciech [mailto:skulski at pas.rochester.edu]
> Sent: Thursday, 7 January 2021 5:26 PM
> To: chris at cfbsoftware.com; ETH Oberon and related systems
> Subject: Re: [Oberon] LOOP conversion
> Chris:
> >How much of your time would you be prepared to invest to learn how
> to
> >add LOOP and multiple EXITs to Wirth's published Project Oberon
> >Oberon-07 compiler?
> I have no idea how to start, so I cannot answer this question.
> >If you give a reasonable answer I am prepared to give you (and
> anybody
> >else watching this list) step by step instructions of the approach
> you
> >can take to achieve it.

It took me 45 minutes to implement but I haven't thoroughly tested it yet. I
would have thought you would need to spend a few hours studying the sections
of the Project Oberon book that I'll be referring you to and another few
hours getting your version of the code to work. Can you spare that amount of

> Please do, but not on the list, but as written PDF document which
> will be a much better reference. Or perhaps a PowerPoint, which will
> be even better.

Sorry - that won't work for me. All the information you need is already
available in PDF documents. I'm not going to rewrite them, just point you to
the relevant sections. I need your feedback after each step to determine how
much you have understood and where to go next.

> You can send it to the list, but I prefer a regular document over e-
> mails. It is just more useful.

I'm not doing this just for your benefit. I'm hoping that other list members
might gain something as well.

> > As far as compiler modifications go it is relatively
> straightforward.
> How many years of education have you invested before being able to
> implement the straightforward modification?
> I know that Andreas has earned a PhD in this field before he wrote
> his little compiler. So I am asking seriously.

My University qualification was a B.Sc. in Physics. The computing part of
the course consisted of a 1-week crash course in programming back then. I
did do a Postgraduate diploma in Computer Science some years later but they
used the notorious 'Dragon Book' by Aho & Co to teach compiler construction
and I found it to be completely incomprehensible and learnt absolutely

Everything I know about compilers I have learnt solely by studying Niklaus
Wirth's Compiler Construction and the Project Oberon books. No more, no
less. That is all you should need to do as well. However, you don't need to
understand it in its entirety to start to make changes. What I am planning
to do is to shine the spotlight on the existing source code to help you to
implement your immediate needs and hopefully give you the confidence and
inspiration to proceed further under your own steam. You'll then be able to
implement the system of your dreams with being at the mercy of anybody else.

> I should pay back, should I not? I promise to teach you FPGA PCB
> board design. It will pay handsomely, so please start learning. 

Thank you for the offer but it is sufficient reward for me if you just pay
forward, you don't need to pay back.

Chris Burrows
CFB Software

More information about the Oberon mailing list