While I know it is subjective, it is still my person pet-peeve. Abbreviations like DL and DMS are really hard to read and remember. What I would have used instead is List and Map.

That's fine. I like to use these because they are visually distinct identifiers (and short), List and Map look like the type (class) names. I know it's a different namespace, but still..

hlint rules are nice for enforcing this, eg. you put sg. like this in your .hlint.yaml:

  - modules:
      - { name: [Data.List], as: List }
      - { name: [Data.Map, Data.Map.Strict], as: Map }

and then you get a hlint warning if you use DL/DMS instead of List/Map

``` *(&i+1)='1'; ```

This line is UB, no? You are referencing some random, if adjacent, block of memory. Anything can happen.