A place where anything is possible but nothing of interest is
computer science by showing that all machines and languages
capable of expressing a certain very primitive set of
operations are logically equivalent in the kinds of
computations they can carry out, and in principle have
capabilities that differ only in speed from those of the most
powerful and elegantly designed computers. However, no
machine or language exactly matching Turing's primitive set
has ever been built (other than possibly as a classroom
exercise), because it would be horribly slow and far too
painful to use.
A "Turing tar-pit" is any computer language or other tool that
shares this property. That is, it's theoretically universal
but in practice, the harder you struggle to get any real work
done, the deeper its inadequacies suck you in. Compare
A tar pit is a geological occurence where subterranean tar
leaks to the surface, creating a large puddle (or pit) of tar.
Animals wandering or falling in get stuck, being unable to
extricate themselves from the tar. La Brea, California, has a
museum built around the fossilized remains of mammals and
birds found in such a tar pit.
(1998-06-27)