Occurs depending on mappings

[tr11]

I have a few copybooks that have groups occurring depending on a flag on some field as follows:

   02 FIELD_TYPE                  PIC X.
   02 RECORD_TYPE_A OCCURS 0 TO 1 TIMES DEPENDING ON FIELD_TYPE.
       ....
   02 RECORD_TYPE_B OCCURS 0 TO 1 TIMES DEPENDING ON FIELD_TYPE.
       ....

In this example, if FIELD_TYPE is A, then only RECORD_TYPE_A is defined. Same for B.

Maybe we could support something like this by allowing OCCURS clauses to point to non-integer fields together with some sort of mapping.
If this sounds good, I can come up with a PR that does this.

[yruslan]

Yes, this makes sense overall. But how a mapping can be defined? Is it a part of the copybook or need to be specified via .option(...)?

[tr11]

It would have to be done through an option. I'm not sure if this is standard at all, but the files I have are structured this way.

[yruslan]

Makes sense. Could you please give an example of such a mapping? Can it be several mappings for different OCCURs?

How urgent is this? The current plan is to

• release 0.5.5 with what we have,
• merge changes prepared for 1.0.0 and work on other issues.

Have pressure from other projects, was planning to work on releasing 1.0.0 sometime next week.

[tr11]

No hurries at all.

The idea would be to specify for each field that depends on something else a mapping. With the example I had before:

   02 FIELD_TYPE                  PIC X.
   02 RECORD_TYPE_A OCCURS 0 TO 1 TIMES DEPENDING ON FIELD_TYPE.
       ....
   02 RECORD_TYPE_B OCCURS 0 TO 1 TIMES DEPENDING ON FIELD_TYPE.
       ....

A possible OCCURS mapping (json) would be

{
  "RECORD_TYPE_A": {
    "A": 1
  },
  "RECORD_TYPE_B": {
    "B": 1
  }
}

[tr11]

Actually, a better example would be

   02 FIELD_TYPE                  PIC X.
   02 RECORD_TYPE_A OCCURS 0 TO 2 TIMES DEPENDING ON FIELD_TYPE.
       ....
   02 RECORD_TYPE_B OCCURS 0 TO 2 TIMES DEPENDING ON FIELD_TYPE.
       ....

and the JSON mapping

{
  "RECORD_TYPE_A": {
    "A": 1,
    "X": 1,
    "Y": 2
  },
  "RECORD_TYPE_B": {
    "B": 1
    "X": 1,
    "Z": 2
  }
}

[yruslan]

Yes, this makes sense. Thanks!