I worked with a VARIANT of that, known as HL7 v2 I at least had a methodology to work it out on another ETL tool but the company, being a medical service provider, already had a special purpose ETL tool. I guess it couldn’t do much, because they didn’t use it for regular ETL, but what we did was I created a little star with a place for all of the available fields, and told them how to locate them, and where to put them. They used that product, and I just then read the fields from the highly normalized star structure I setup. They were happy with it for the 4 years I was there, and apparently are still happy with it.
The complexity depends on how the data is setup in the message, how you read it, and possibly the number of arrays that you have. The message that you have here makes it look like you may not have to worry about arrays. The characters in the first part of the line indicate what this relates to and then the * indicates that you are dealing with the next part of the line.
It LOOKS like Snaplogic may actually have a snappack for EDI, that has a lot of the grunt work handled by some template or something. If this is the case, you might find it worthwhile talking to your representative about this. Their snappack would effectively be doing be doing the same thing that the tool the company I spoke about was using!
Based on what I can see about the EDI snappack makes it seem like it effectively takes the EDI input, that it pulls, and converts it to an easy to read JSON that snaplogic handles throughout. If I were doing it without such a thing, I would be tempted to use another script. You can do that, and it would seem transparent, but it is more work, and less obvious.