Interpreting Selection Subjects and Selection Objects

Operands before the WHEN phrase

Individually, they are called selection subjects.
Collectively, they are called a set of selection subjects.

Operands in the WHEN phrase

Individually, they are called selection objects.
Collectively, they are called a set of selection objects.

ALSO
Separates selection subjects within a set of selection subjects; separates selection objects within a set of selection objects.
THROUGH and THRU
Are equivalent. Two operands connected by a THRU phrase must be of the same class. The two operands thus connected constitute a single selection object.
The number of selection objects within each set of selection objects must be equal to the number of selection subjects. Each selection object within a set of selection objects must correspond to the selection subject having the same ordinal position within the set of selection subjects, according to the following rules:
IBM Extension
End of IBM Extension
See also: