Where should the type information be 334

COPIES is limited to our imagination, since it doesn't exist in COBOL. It was a hypothetical clause RPL introduced to clarify his point.

COPY isn't limited to any level, or even to the data division. It can be used on any line of a COBOL compliation unit, to include anything. And there's the REPLACING phrase, which will subsbreastute one text sequence for another in the copied-in source, which is relevant here because you can use it to change the level number of a structure you're copying in.

So if I have a copybook (ie a file of source code intended to be COPY'd in) named "foo.cpy" containing:

10 foo. 15 bar pic x.

I can do:

01 just-foo. copy "foo.cpy".

01 thing-with-foo. 05 stuff pic x. 05 thing-foo. copy "foo.cpy".

01 thing-with-thing-with-foo. 05 subthing-1. 07 subthing-2. copy "foo.cpy".

copy "foo.cpy" replacing ==10== with ==01==.

The copied-in structure can be inserted anywhere its topmost level number fits, and with "copy replacing" I can wedge it in even where it doesn't.

There's nothing earth-shattering about it (it's not so different from C's #include, except for "replacing", and that's not hard to achieve in C with macros); I just brought it up to show how COBOL permits the reuse of definitions. It's not as convenient as in C, where struct (and enum and union) creates a distinct type, but it's there.

Micro Focus COBOL also offers the "typedef" clause, an extension which creates a new type from a data division level-01 item; then that type can be used with the "usage" clause in subsequent items. That's closer to C's struct, but it's not standard.

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I will shoue the world one of the grate Wonders of the world in 15 months if Now man mourders me in Dors or out Dors -- "Lord" Timothy Dexter, A Pickle for the Knowing Ones