During my learning of nim, I'm trying to implement some kind of code common for
Python OOP. I'm spent a lot of time reading articles, book, forum and feels
like I'm more or less OK with basics.
But today I meet strange bug (as I initially think), which is explained in 3
listings below...
File **ex.nim**
type Entity*[T] = ref object of RootObj
props*: T
id*: int
name*: string
proc uuid*[T](entity: Entity[T]): int =
echo "Running base class uuid ..."
entity.id
Run
File **ex2.nim**
import ex
type UserProps* = object
username*: string
type User* = ref object of Entity[UserProps]
Run
File **ex3.nim**
import ex2
# import ex
let up = UserProps(username: "Telega")
let u = User(props: up, id:8)
# src/ex3.nim(8, 7) Error: undeclared field: 'uuid' for type ex2.User
[declared in src/ex2.nim(7, 6)]
echo u.uuid
Run
If we try to compile `ex3.nim` it will fail with error `undeclared field:
'uuid' for type ex2.User`. When code listed in the file `ex3.nim` was in
`ex2.nim` all works OK. When I move code to the new file, there is an error.
Then I realize, that importing import ex fixes the error. But I was surprised
by this.
And only then I realize, that `u.uuid` is actually `uuid(u)` and this procedure
was not imported.
So, that is not a history about my smartness :)
My questions are:
* What is a nim way to write such code? (I'm thinking about `include`, but
not sure, this is the true way.)
* In other words, how should I notify users of my code, that they have to
import additional modules?
* How to explain this approach/behavior to Python people? (I'm already
explained this to myself, but I do not know how to live with this knowledge
comfortably)
I'm pretty sure, that trying to reflect what I was doing in Python for many
years is not follow nim-way, but that is my learning curve, so any links to
good examples or explanations are welcome, coz I saw a lot of examples of a
library-, utility-, framework- related code, but almost no examples of boring,
enterprise-related stuff.
Thanks.
