First-class

In computer science, values may be of first-class, second-class, or third-class:

	assignable	passable as parameter	passable as return value[?]
First-class	yes	yes	yes
Second-class	yes	yes	no
Third-class	yes	no	no

In many programming languages, labels are third-class values while numerical values are first-class values. A few languages use this kind of exact distinction.