RE: succinctness = power

["Anton van Straaten" <address@hidden>]

Jeffrey Palm wrote:
> Given this definition, no... but this definition is inaccurate,
> because 'succinct' doesn't imply the *greatest* compression;
...
> So, I'd say languages *should* aim for a succinctness that
> reduces the size (and consequently the complexity) of
> programs without hindering their expressiveness.

I think what is wanted with programming languages and programs intended for
human consumption is something along the lines of "the greatest
meaning-based compression" (or "greatest semantic compression", to be more
succinct).  If greatest possible compression were the goal, then all that
would be needed to write succinct programs would be to run the final program
through
a compression program like gzip.

Compression programs work by looking for repeated patterns in the data being
compressed, and optimizing the expression of those repetitions.  But most
compression programs look for arbitrary identical patterns, and don't care
about possible meanings of the data being compressed.  Writing succinct (or
concise) human-readable code involves identifying repeated patterns that
have closely related meanings, and optimizing those.

This kind of "manual semantic compression" results in better code, or even
best code.  That's because repetition is almost always bad, in almost every
possible respect (one common exception: execution speed).  A semantically
compressed program should, almost by definition, be more comprehensible to a
human than the alternatives.  Semantic compression of programs tends to
result naturally in layered and modular programs, since if one is paying
attention to meaning when performing compression, common functionality is
factored out, and higher-level behaviors are built on top of lower-level
behaviours.

So I would need to be convinced that there's any technical case at all, as
some have suggested, for not performing maximal semantic compression on
programs.  In that case, Fredrik's definition of succinctness as "greatest
possible compression" works just fine, as long as it's understood to be
semantic compression.

Of course, there's a pragmatic/business case for not performing maximum
semantic compression, which is simply that many programmers and designers
are either not capable of doing it, or else they work in environments in
which the benefits of approaching development in this way are not understood
or sufficiently valued.  Also, in some cases with sufficiently small,
one-off programs, high levels of semantic compression may not be directly
justifiable.

Anton