I don’t know Malli; and I haven’t used Clojure since 2017, so things might have changed. So if I’m misunderstanding the purpose of that library, my mistake.
The issue wasn’t that we would use the wrong data in the wrong place. The issue is that we had a bunch of data that was syntactically similar (huge overlap in keys), but semantically different (key numerical results must be calculated differently based on the minor differences between maps).
So the issue is less “the right data got to the wrong place” and more “in this data pipeline there are multiple places where the same data must be treated differently based on minor differences”. This is actually pretty tricky to do in a maintainable way in Clojure; technically possible but really hard to avoid breaking when you need to extend it.
In the end it actually turned out to be an issue that classes and objects solved brilliantly. The solution was to have the pipeline accept an interface (syntactic similarity) and have different classes for the behavior (semantic differences).
The issue wasn’t that we would use the wrong data in the wrong place. The issue is that we had a bunch of data that was syntactically similar (huge overlap in keys), but semantically different (key numerical results must be calculated differently based on the minor differences between maps).
So the issue is less “the right data got to the wrong place” and more “in this data pipeline there are multiple places where the same data must be treated differently based on minor differences”. This is actually pretty tricky to do in a maintainable way in Clojure; technically possible but really hard to avoid breaking when you need to extend it.
In the end it actually turned out to be an issue that classes and objects solved brilliantly. The solution was to have the pipeline accept an interface (syntactic similarity) and have different classes for the behavior (semantic differences).