Part of the Occam utility.
Laurent Siebenmann <lcs@topo.math.u-psud.fr>
Master posting 1994, ftp ftp.math.u-psud.fr
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****** OCCAM'S RAZOR AND MACRO MANAGEMENT
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****** Laurent Siebenmann
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****** lcs@topo.math.u-psud.fr
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THE APHORISM:
entia non sunt multiplicanda praeter necessitatem
entities should not be multiplied beyond necessity
William of Occam 1285-1349(?)
\footnote{Occam's Razor is not just a trendy novel of this
decade; it is the aphorism quoted! Experts believe that Occam
did not formulated it in exactly these famous words, but rather
as
What can be done with fewer assumptions
is done in vain with more.
or
Plurality is not to be assumed without necessity.
The term Principle of Parcimony is also used for the Razor.}
THE SOFTWARE:
--- occam.pub
--- auditor.tex
--- DefStrip-QUEDM-Macros (Macintosh only)
--- defstrip.hlp help file for above
--- occam.spc specifications for source macro files to be minimized
--- defstrip.tex (is mere wishful thinking in summer 1994)
MASTER POSTING in 1994:
--- ftp ftp.math.u-psud.fr directory pub/TeX/defstrip.dir/
Have you ever felt guilty about burdening a friend with
macros that are not really necessary for composing your
typescript? I certainly have; and would ideally like to
follow Knuth's example of using macro files which define
exactly what is necessary for a document and nothing more.
However, pruning a macro file that has served for
another purpose is a pain. Most of us respond to this pain
by adopting a rather messy maximalist approach in which all
the macros that have a geneology related to the necessary
macros are transmitted.
But there is another approach! One can seek efficient
mechanisms to ease the task of weeding out unnecessary macros.
One such mechanism is auditor.tex, which sets up a list of
names of those macros of macro file that turn out to be
*unnecessary* in a given typescript.
A complementary tool is the utility DefStrip which
combines a specially arranged version of the macro file to be
"cleaned up" with the list of unused macros provided by
auditor.tex to delete the unneeded macros listed together
with some related material.
Ultimately, DefStrip will hopefully be a ".tex" program
"defstrip.tex" resembling the "docstrip.cmd" utility of LaTeX
fame. At the present time there exists instead a QUEDM script
called DefStrip-QUEDM-Macros; QUEDM is a editor with convenient
"macro" (=composite command) capabilities that is available on
Macintosh computers.
DefStrip and Auditor together make up a system called
"Occam".
Let us consider two plausible examples of use of the Occam
system. Only the first has proved genuinely useful thus far.
(A) Many TeX users build up a cumulative personal macro file
through composing many articles with TeX. A time inevitably
comes when it is embarrassing, cumbersome, or confusing to
submit the whole macro file along with the article. The Occam
system makes the pruning of the macro file painless. It is
advisable to tidy up the macro file and maintain it in "Occam"
format as explained in "occam.spc"; then and only then will
auditor.tex and DefStrip collaborate to *automatically*
produce a minimal version of the macro file suitable for the
article at hand.
(B) Suppose that one proposes to post in electronic ".tex"
form an article prepared using the TUGboat macro package.
(The alternative ".dvi" form is less flexible; for instance the
".tex" version can be reformatted to be read in comfort on any
computer screen whereas a ".dvi" version often does not have an
appropriate width.) Such a macro package is not immune to
alteration with time and unfortunately the principles of
upward compatibility are pious hopes, not laws. Consequently,
one is well-advised to post, along with the article the macros
necessary to compile it --- especially if modifications to
the macros have been used. Unfortunately, the TUGboat macros
are more voluminous than most articles. This is an unfortunate
obstacle to electronic posting of ".tex" typescripts.
An attractive solution would be to have a version of the
TUGboat macros that have been set out in a form suitable for
use with Occam. Then the necessary macros for a
given article can quickly be extracted from the total package
to make the total posting both compact and archival.
The archival nature of such TeX postings still depends on
Knuth's Plain format being archival. Plain probably will be at
least upwards compatible in the best sense. However, the
article (or a book, say) could perhaps be made archival on the
scale of many decades by subjecting the Plain macros to the same
process as the TUGboat macros; this incidentally seems necessary
to realize best economy. The article would then have its own
format built with initex. This may seem needlessly radical to
an English speaking user. But I consider bootstrapping from
initex the best approach for fully archival ".tex" postings
where other languages are concerned.
Afterthoughts
1) Occam as presently realized does not make much sense in the
LaTeX world. The LaTeX group is building official macro modules
that cover all needs and are univerally available. I suspect this
will require continuing exponential growth of the LaTeX project,
of the computers that run LaTeX, and of the of the time invested
by LaTeX users. I may be wrong.
2) Bootstrapping on initex as mentioned above seems to have a
parallel in classical programming, namely the use of assembly
language --- whereas the LaTeX approach is parallel to the
use of a big and constantly evolving interpreter.
3) Occam's razor was one of the guiding principles of
scientific thought in the era before the coming of age of
computers. I suspect the philosophy of Aristotle or Descartes
is far more likely to appeal to computer scientists. One might
go so far as to say that Occam's razor has by now been
discarded --- indeed object oriented programming consciously
cultivates the art of multiplication of entities, and this
sort of thing is to be found in TeX in commands such as
\newheading of LaTeX. What can the minimalism of Occam's
razor offer TeX users at this late date? Probably just a few
things.
(a) Friendliness to human beings. Unnecessary entities
that cost a microprocessor only a fraction of a second can cost
the human mind a significant amount of time.
(b) Extra storage space and computing power. Both are in a
period of exponential growth. But so is the TeX software we
use. Where performance in a fixed task is concerned these
growths may even cancel one another. When this happens the
old-fashioned minimalism of Occam's razor can
help derive pleasure from progress.
Laurent Siebenmann
<lcs@topo.math.u-psud.fr>