Improve showEntities

[Masynchin]

I have check the last commit from @ad-si where he added showEntity function. I saw a pattern, and started to rewrite it to more maintainable form.

Goals:

• [x] Remove lambda.
• [x] Add Show function for each Entity attribute.
• [ ] Move newline adding from "Entity attribute" functions.
• [ ] Use fromMaybe only ones.

My changes didn't break any tests. But I didn't check manually, so I maybe break some format (tests for showEntites use only zeroes, no coverage for other than Id attributes).

---

This is my first contribution to this project and I can share you my experience with it.

There is no CONTRIBUTING file (I expect its link in README), so I have no exact instruction to follow. Without it I have to manually search for testing tools. After I found command for running tests, I run it before any changes, and it shows me "51/55 tests passed", and "1 test pending" 🤨. After my changes I opened this PR (without opening related Issue, that is one of CONTRIBUTING things I check for).

Here is the list of things I think can improve contributors experience:

• CONTRIBUTING file.
• Tests passing status.
• Issue types (and should it be created before PR).

I hope this summary can help this project.

[Masynchin]

Sorry for claiming there is no CONTRIBUTING, I just found development.md. I found test commands here, but no info about contributing. I think this development.md need to be renamed to CONTRIBUTING.md or be mentioned in README.

[Masynchin]

My last two goals is to remove repeating logic with fromMaybe and <> "\n", but fixing this I do code like:

showEntity :: Entity -> String
showEntity (Entity entity) =
  [ entity.id # showId # Just
  , entity.name <#> showName
  , entity.note <#> showNote
  , entity.utc <#> showUTC
  , entity.tags <#> showTags
  , entity.accounts <#> showAccounts
  ]
  <#> (map (_ <> "\n"))
  <#> fromMaybe ""
  # fold
  <> "\n"

I think this one looks not as understandable as current one. Or it is just for me?

<#> (map (_ <> "\n")) <#> fromMaybe "" can be replaced with <#> maybe "" (_ <> "\n"), but I am not sure this will improve readability. Can this code be improved in terms of readability?

[Masynchin]

I think this one looks not as understandable as current one. Or it is just for me?

It can also be that way:

showEntity :: Entity -> String
showEntity (Entity entity) =
  [ entity.id # Just
  , entity.name
  , entity.note
  , entity.utc
  , entity.tags
  , entity.accounts
  ]
  <#> map withNewline
  <#> showOrEmpty
  # fold
  # withNewline


showOrEmpty :: Show s => Maybe s -> String
showOrEmpty (Maybe a) = show a
showOrEmpty Nothing = ""

withNewline :: String -> String
withNewline = _ <> "\n"

[Masynchin]

@ad-si can you check this?

[ad-si]

Thanks a lot for the suggestions!

• I renamed the development.md file to contributing.md
• I included your changes in a7f5aa1a16c4c4b045a4fefd91c30a7deee2cedd (Sorry, for not merging your branch, but it had conflicts and I needed to clean up the code)