The Jargon File (version 4.4.7, 29 Dec 2003):
juggling eggs
vi.
Keeping a lot of state in your head while modifying a program. ?Don't
bother me now, I'm juggling eggs?, means that an interrupt is likely to
result in the program's being scrambled. In the classic 1975 first-contact
SF novel The Mote in God's Eye, by Larry Niven and Jerry Pournelle, an
alien describes a very difficult task by saying ?We juggle priceless eggs
in variable gravity.? It is possible that this was intended as tribute to a
less colorful use of the same image in Robert Heinlein's influential 1961
novel Stranger in a Strange Land. See also hack mode and on the gripping
hand.
The Free On-line Dictionary of Computing (30 December 2018):
juggling eggs
Keeping a lot of state in your head while modifying a
program. "Don't bother me now, I'm juggling eggs", means that
an interrupt is likely to result in the program's being
scrambled. In the classic first-contact SF novel "The Mote in
God's Eye", by Larry Niven and Jerry Pournelle, an alien
describes a very difficult task by saying "We juggle priceless
eggs in variable gravity." See also hack mode.
[Jargon File]