compact

1. (Or "finite", "isolated") In domain theory, an element d

of a cpo D is compact if and only if, for any chain S, a

subset of D,

d = lub S = there exists s in S such that d #@= s.

I.e. you always reach d (or better) after a finite number of

steps up the chain.

("#@=" is written in LaTeX as sqsubseteq).

[Jargon File]

(1995-01-13)

2. Of a design, describes the valuable property that it can

all be apprehended at once in one's head. This generally

means the thing created from the design can be used with

greater facility and fewer errors than an equivalent tool that

is not compact. Compactness does not imply triviality or lack

of power; for example, C is compact and Fortran is not,

but C is more powerful than Fortran. Designs become

non-compact through accreting features and cruft that

don't merge cleanly into the overall design scheme (thus, some

fans of Classic C maintain that ANSI C is no longer

compact).

(1995-01-13)