Comparisons
Involving Index-Names and/or Index Data Items (Relation Condition)
General Format:

Note that the required relational characters "<"
, ">", and "=" are not underlined, to avoid confusion with other symbols
such as " ? ".
General Rules:
-
Relation tests can be made only between:
- Two index-names. The result is the same as if the corresponding occurrence
numbers were compared.
- An index-name and a numeric data item or numeric literal. The occurrence
number that corresponds to the value of the index-name is compared to the
data item or literal.
- An index data item and an index-name or another index data item. The actual
values are compared without conversion.

An index-name can be compared with an arithmetic expression. The occurrence
number that corresponds to the value of the index-name is compared to the
computed value of the expression.
- The result of the comparison of an index data item with any data item or
literal not specified above is undefined.