The KEEP statement inserts a database key value from a currency indicator
  or keeplist into a keeplist.

  Format -

        [         [        { record-name } ]          ]
        [ CURRENT [ WITHIN { set-name    } ]          ]
        [         [        { realm-name  } ]          ]
   KEEP [ { OFFSET integer-exp }                      ]
        [ { FIRST              } WITHIN keeplist-name ]
        [ { LAST               }                      ]

      USING destination-keeplist

      [ ON ERROR stment ] [ NOT ON ERROR stment ]

      [ END-KEEP ]

1 - record-name

  is a subschema record name.

2 - set-name

  is a subschema set name.

3 - realm-name

  is a subschema realm name.

4 - integer-exp

  is an arithmetic expression or integer.  It refers to a position in
  keeplist-name.  Integer-exp cannot be zero.

5 - keeplist-name

  names a keeplist in the Sub-Schema Section.

6 - destination-keeplist

  names a keeplist in the Sub-Schema Section to receive the database key
  value.

7 - stment

  is an imperative statement.