PERFORM Statement

Context:

    Procedure Division
        Statements

perform-statement

Further information

For JVM COBOL, the USING phrase is only applicable to JVM version 1.7 and onwards.

The type-specifier section of the PERFORM..USING phrase must specify a type that implements the System.IDisposable interface (.NET) or the java.lang.AutoCloseable interface (JVM version 1.7), and must specify an initial value via the = expression syntax.

Example of local declaration within an iterator

A variable can be declared at the point of use in an iterator, and its scope is until the end of the perform block.

      *>   In this case, the scope of i is until the end of the perform block. 
           perform varying i as binary-long from 1 by 1 until i > 10
               display i
           end-perform

      *>   So the i in the following perform block is a new instance of i,
      *>   independent of the i in the preceding perform block.
           perform varying i as binary-short from 0 by 1 until i > 10
               display i
           end-perform

Here, k is declared inline to iterate through a dictionary. Again, it is in scope until the corresponding end-perform.

    01 dict1 dictionary[string string].
           create dict1
           write dict1 from "Anthony" key "A"
           write dict1 from "Brian" key "B"
           write dict1 from "Charles" key "C"
           perform varying key k as string value val as string through dict1
               display k ":" val
           end-perform
           perform varying value val as string through dict1
               display val
           end-perform
           perform varying key k as string through dict1
               display k
           end-perform

See also the Local Variables sample, available from $COBDIR/demo.