资料来源 : Webster's Revised Unabridged Dictionary (1913)
Black hole \Black" hole`\
A dungeon or dark cell in a prison; a military lock-up or
guardroom; -- now commonly with allusion to the cell (the
Black Hole) in a fort at Calcutta, into which 146 English
prisoners were thrust by the nabob Suraja Dowla on the night
of June 20, 17656, and in which 123 of the prisoners died
before morning from lack of air.
A discipline of unlimited autocracy, upheld by rods,
and ferules, and the black hole. --H. Spencer.
资料来源 : WordNet®
black hole
n : a region of space resulting from the collapse of a star;
extremely high gravitational field
资料来源 : Free On-Line Dictionary of Computing
black hole
1. An expression which depends on its own value or a technique
to detect such expressions. In graph reduction, when the
reduction of an expression is begun, the root of the
expression can be overwritten with a black hole. If the
expression depends on its own value, e.g.
x = x + 1
then it will try to evaluate the black hole which will usually
print an error message and abort the program. A secondary
effect is that, once the root of the expression has been
black-holed, parts of the expression which are no longer
required may be freed for garbage collection.
Without black holes the usual result of attempting to evaluate
an expression which depends on itself would be a stack
overflow. If the expression is evaluated successfully then
the black hole will be updated with the value.
Expressions such as
ones = 1 : ones
are not black holes because the list constructor, : is lazy so
the reference to ones is not evaluated when evaluating ones to
WHNF.
2. Where an {electronic mail} message or {news} aritcle has
gone if it disappears mysteriously between its origin and
destination sites without returning a {bounce message}.
Compare {bit bucket}.
[{Jargon File}]