[quote=“peerreynders, post:8, topic:6342, full:true”]
First I would like to say thank you for taking the time to write everything that you wrote , that also includes everyone else. I wanted to reply to multiple people with this single reply but not sure how…
Now in regards to the principle of separating thought concerns I think that I get the the picture, but where I kind of get lost is when you need to interact with a database or an entity that holds your state for example processes, ets, mnesia, etc.. Usually one would tend to write their module based on their data storage format. For example a User module would probably be defined as struct so you could give it the id, name, and other attributes. But with the approach of the @sasajuric and from reading everyone else reply - it seems like the the system itself and whatever data storage you use(even memory) would be a complete different entity, if I may say a complete different system that would interact with your main system. I’m I wrong ?
So in other words one would have to create a separate client that would handle retrieving data in the storage and transform it in the format the main system module requires it to be in to be able to continue processing the data.
So the picture that I have is for example: System <— Client ----> Data storage .
(I’m very visual so pictures, some kind of representation or code are very helpful.)
The reason why I am mentioning data storage is because I still feel uneasy with the part that in fp you don’t have some kind of object/class to hold your state. On contrary in fp one would use a function that would either have the whole state as an argument or some separate module such as a process that would hold the state.
) inside of functions and write other functions that know how to manipulate those queries and their results (perhaps with structs). Those functions create the surface with which you call out into these “separate systems”, and when using those functions your program can generally ignore the “detail” that they are separate from your program.