[Oberon] Use of resources.

[Jan de Kruyf]

hallo Frans-P

To me the issue is the thinking patterns needed for effective software design.
After all that is why they come to school, to learn!

One helpful way of thinking is "separation of concerns."
see

 https://www.cs.utexas.edu/users/EWD/transcriptions/EWD04xx/EWD447.html

When you search for "Dijkstra separation of concerns" you will find
more links. The wikipedia article is unfortunately a bit advanced and
so it obfuscates the essence.

Another helpful thinking pattern is "progressive refinement". Wirth
tried to teach that way.
The green Oberon book has examples and there is a paper from him on
the 8 queens problem where he tries to highlight the thinking pattern.

so if I must speak for my muddy self: Often I dream up some seemingly
useful structure to start from, but then as I progress I might find
that "it just looks too complex" mostly because I did not think things
through to the very esssence of it, or beause
i try to do 2 things at once, and none gets done right. So back to the
drawingboard and with the experience gained we start all over again,
etc.


cheers,
j.





On 12/16/15, Frans-Pieter Vonck <fp at vonck.nl> wrote:
> Yes, one page per module seems ridiculous, and one page per procedure
> seems fair.
>
> What strikes me is that my students show me piles of listings of code
> that reminds me of the windings green lineprinter paper I walked around
> with in the eighties. Pascal on the VAX. The programming projects of my
> students are self chosen, extracurricular activities and the need for
> structured programming emerges naturally in their learning path. By the
> way, I'm happily surprised they still feel a need to actually print
> their code on paper.
>
> So the idea is the let them discover a sort of 'rule of thumbs' for the
> intellectually manageability of programs. (Wirth - On the composition of
> Well-structured programs). And then show them the wise steps to refine
> their code.
>
> Also, as I scrolled through the Project Oberon book I found that the
> definition listings of the modules were around one book page.
> Tomorrow I will make a hard copy of the Oberon book and to get a feeling
> of the intellectually manageability of Project Oberon.
>
> Greets,
> Frans-Pieter
>
> Chris Burrows schreef op 2015-12-15 22:40:
>> 'One page per procedure' possibly but definitely not 'one page per
>> module'.
>> I don't recall seeing a quote but I have always used a *rule of thumb*
>> that
>> if you can't see all of a procedure at once then you should *consider*
>> refactoring it. Hence what might have been 'a page' in the past might
>> now be
>> 'a screenful'. This is deliberately vague e.g. if I regularly use one
>> of my
>> widescreen monitors in portrait orientation with a relatively small
>> font I
>> can see a lot more than otherwise might be posible.
>>
>> However, you should be very careful when communicating guidelines of
>> this
>> sort to inexperienced programmers to make sure they they don't
>> interpret
>> them as commandments set in stone. Otherwise they might arbitrarily
>> break up
>> large procedures into smaller illogical chunks just because they have
>> been
>> given a rule to follow. You should give some examples of horror cases
>> that
>> obviously need splitting up and other examples of procedures that are
>> large
>> for a good reason (e.g. a case statement with many cases),
>>
>> Regards,
>> Chris Burrows
>> http://www.cfbsoftware.com
>>
>>
>>> -----Original Message-----
>>> From: Oberon [mailto:oberon-bounces at lists.inf.ethz.ch] On Behalf Of
>>> Frans-Pieter Vonck
>>> Sent: Wednesday, 16 December 2015 7:09 AM
>>> To: oberon at lists.inf.ethz.ch
>>> Subject: Re: [Oberon] Use of resources.
>>>
>>> Hello Paul, Peter and all other oberonneurs,
>>>
>>> one of my former highschool students is writing a Python programmes
>>> that have very long listings. Despite the structured nature of Python
>>> his programmes become to complex to explain to me.
>>> Now I think I remember a quote from Niklaus Wirth where he states
>>> that every module that is longer than one page should be rewritten in
>>> separate modules.
>>> Did anyone remember this quote? And, do you think this adagium is
>>> only valid for the Main Module or is it also applicable for, say math
>>> library modules?
>>>
>>> Greets,
>>> Frans-Pieter
>>>
>>
>>
>> --
>> Oberon at lists.inf.ethz.ch mailing list for ETH Oberon and related
>> systems
>> https://lists.inf.ethz.ch/mailman/listinfo/oberon
>
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