Any of the flow control constructs (not an IF statement) can be assigned a
construct name, followed by a colon on the first line
of the construct. If a name is used, the corresponding END statement that ends
the construct must be followed by the same construct name. Construct names are
not labels associated with the GOTO statement (although they behave like labels
when used with DO, EXIT and CYCLE statements). They are simply used as
annotations in order to match an END with its beginning.