Re: Redefining a DS

Barbara Morris wrote:

On 4/8/2010 11:40 PM, Dennis Lovelady wrote:

But here's my feeble attempt anyway. I had to assume certain attributes
about the array, but you get the jist. In case you don't, the key below is
that a 9-byte packed number takes up 5 characters. So I've defined
elem2Thru10 as a 9*(elem_len) byte array starting at position (elem_len)+1.

D array1DS DS
D myNumbers 9P 2 Dim(10)
D elem2Thru10 45 Overlay(array1DS: 6)

/Free

// Move 9 to 10, 8 to 9, 7 to 8, et cetera
elem2Thru10 = array1DS ;

You can avoid defining the extra subfield by using %SUBST on the data structure.

%subst(array1DS : %size(myNumbers) + 1) = array1DS;

Okay, THAT one made me think... and now that I've thought about it I love it. I do, though, share Dennis' question about how the system effectively performs a right-to-left move. I've also done assembly language programming that uses a move from left to right to initialize a buffer.

Joe