I am accused of not offering DeMillo 2.
and Lipton an opportunity to respond prior
to publication of my Editor’s Letter. As Editor-in-Chief I write such bimonthly Editor’s
Letters in which I often express opinions on
controversial matters. The proper way to
disagree with them, and many people do, is
to leave comments online or submit a letter
to the editor. This is standard operating procedure in all publications I am aware of.
As Editor-in-Chief, I am committed to a
scrupulous peer-review process for submitted articles, but I have not taken a vow of
silence, nor does it make sense for me to do
so. Furthermore, I gladly welcome the Editor-in-Chief in 2040 to reexamine my editorial decisions.
It seems that DeMillo and Lipton were 3.
offended by my use of the word “misguided.”
But one should read the full context of the
word: “With hindsight of 30 years, it seems
that DeMillo, Lipton, and Perlis’ article has
proven to be rather misguided. In fact, it is
interesting to read it now and see how argu-
ments that seemed so compelling in 1979
seem so off the mark today.”
In the paragraph that preceded these
sentences, I referred to two Turing Awards
given for works in formal verification. Due to
lack of space, I did not include references to
two ACM Kanellakis Awards and two ACM
Software System Awards for works in for-
It is in this context that I expressed an
opinion that the 1979 article, which implied
the futility of formal verification as an activ-
ity and, by implication, as a research area
was “misguided,” with “hindsight of 30 years”
in spite of “its compelling arguments.”
DeMillo and Lipton disagree with my 4.
opinion that “the editors of communications
in 1979 did err in publishing an article that
can fairly be described as tendentious with-
out publishing a counterpoint article in the
The subject (and title) of my editorial was
“More Debate, Please!” The article in ques-
tion is one of the most controversial and in-
fluential ever published in communications.
I read it as a graduate student and was
deeply affected by it. I singled it out because
it was the perfect example for making the
point of my editorial, which did not focus on
analyzing the 1979 article. Rather, its main
point was that, in my opinion, even with 30-
year hindsight, the editors in 1979 did abso-
lutely the right thing in publishing it.
It is precisely because the 1979 article
was so influential that I chose it as an exam-
ple. I honestly feel that its authors should be
pleased that it is still trenchant, even if some
people disagree with its major thrust.
of procedural abstraction is provided
by Scratch’s “broadcast” mechanism.
That’s why we added parameterized
procedures to some experimental versions of Scratch, though we have not
yet come up with a design that satisfies
our goals of simplicity and understandability. We’re continuing to experiment, hoping to include more forms
of abstraction in future versions.
the Scratch team, cambridge, MA
Give Scratch an Abstraction
I welcome the efforts described by
Mitchel Resnick et al. in “Scratch: Programming for All” (Nov. 2009) to familiarize more people with programming.
However, when I downloaded Scratch
from the Scratch Web site (http://
scratch.mit.edu) and looked over the
Scratch programming constructions,
I found no convenient abstraction
mechanism, as in, say, a facility to define and call parameterized functions.
Such a mechanism could be viewed
as advanced and not easily digested by
the intended users of the Scratch programming language. But some projects on the Scratch Web site feature
significant code redundancy and could
be reduced in size and simplified if the
code could be restructured through a
few suitable functions.
Though not all Scratch programmers
would be comfortable with an abstraction mechanism, it seems a pity that
something so fundamental does not
even exist, and so cannot be conveniently demonstrated and disseminated.
Second in importance and also
missing from the Scratch programming language is a data-structuring
thorkil naur and Karen Brahes,
Recognition for the
I was heartened by Wendy Hall’s interest, as expressed in her President’s
Letter “ACM Europe” (Oct. 2009), in
student chapters, award nominations,
and conferences sponsored by the
ACM in Europe.
I regularly seek out opportunities
for public recognition and awards
for ACM members not affiliated with
universities. For example, the traditional rule requiring three or more
endorsements for a researcher to be
considered for an award is a barrier to
would-be nominees not affiliated with
universities or in the pool of preferred
students of their academic mentors.
The situation is even more problematic if an individual’s research is based
on his/her long-standing experience in
an area of expertise not currently “
popular” in universities.
I therefore suggest the ACM in Europe establish a committee to consider self-nominations and invite
volunteers from among the young researchers who promote computer science in their spare time, rather than as
Concerning conferences and other
events, I’d also like to propose ACM
set up summer schools open to all
enthusiasts who promote electrical
engineering and computer science.
Locating them in popular tourist areas
would be another way for ACM in Europe to increase interest in more traditional ACM activities and individual
miroslav Skoric, novi Sad, Serbia
Abstraction is an important computational concept, and a simple form
Communications welcomes your opinion. To submit a
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