Earlier quoted context omitted.
Could you share an example of this? I could be misinterpreting this but say you're building a survey system and you need to keep track of answer types (e.g. text, date, etc) and the answer itself, how can you collapse that into one field?
Your thermos does not have a switch which you must set to "hot" or "cold" before inserting a liquid, handles solids as well as liquids, and doesn't require you to even think where the theshold might lie between the "hot" and "cold" settings. Instead it just does its best to prevent an energy exchange in either direction without having to even know the variables involved. And the "same subroutine" is basically used fo…
Languages with Sum Types represent this much more elegantly with arbitrary numbers of variants and force you to check which one you have before accessing the more specific data (e.g. the filter) inside.