[Oberon] RE: PIC (was Re. Staapl)

Chris Glur easlab at absamail.co.za
Tue Jul 29 05:23:33 MEST 2008

> > 
> > The whole ideas of pic: minimal dil-devices; seems to
> > have morphed to absurdity  - like upgrading a 
> > wheel-barrow to a locomotive !
> > 
Chris Burrows wrote:-
> Not for everybody - read about Wirth's recent PIC-related work here:
> http://www.inf.ethz.ch/personal/wirth/Articles/Miscellaneous/index.html

Wow ! The value of serendipit/dy.
This thread only got here because I wrongly failed to update my
EditKeys.Definitions ^ 's
default field from oberon at lists.inf.ethz.ch

Yes, Wirth has stuck with the original small DIL version.
I hope I can still buy them.
Usually they start with a '2 cylinder version' and later you can only
buy the '8 cylinder version'.

It's beautiful how Wirth has used eg.
!x.4   == set bit 4 of variable x
!~s.3   == clear bit 3 of variable s
?~B.6  == wait for bit 6 of [variable B eg.] the acknowledgement-signal

Compare this snappy syntax to the 'set-based' nightmare of x86-native.

OTOH I'm confused that he writes: ----------
> Conditional statements have the form shown at the left and explained in
> terms of conventional notation to the right.
> [cond -> StatSeq]                          IF cond THEN Statseq END
> [cond -> StatSeq0 |* StatSeq1 ]    IF cond THEN Statseq0 ELSE StatSeq1 END
> [cond0 -> StatSeq0 | cond1 -> StatSeq1]
>             IF cond0 THEN Statseq0 ELSIF cond1 THEN StatSeq1END
> Repetitive statements have the form:
> {cond -> StatSeq}                    WHILE cond DO Statseq END
> {cond0 -> StatSeq0 | cond1 -> StatSeq1}
>                      WHILE cond0 DO Statseq0 ELSIF cond1 DO StatSeq1 END
Which syntax WE don't like as much as OUR familiar:
>      MODULE Conditions;
>         INT x, y, z, w; SET s; BOOL b;
>       BEGIN
>         IF x = y THEN z := 0 END ;
>         IF x = y & y # z & z >= w THEN z := 0 END ;
>         IF x < y OR y <= z OR z > w THEN z := 0 END
>       END Conditions.
 which he writes in his same *.pdf explanation.

Aubrey.McIntosh wrote:
]Interesting.  Has anyone downloaded the compiler?

No I can't find it even with:

If someone points me to the compiler, I'll do a simplified
report-back on some compile-test runs, because I've got the
hardware here.


== Chris Glur

More information about the Oberon mailing list