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.