I’m a person who used Python heavily and just learn some C++ before using Julia.
To me, Python is a world where you have file/folder as module and package, and import it if you need to use it, no matter it’s your code or others package, you know where the code is coming from within every single file.
People from python is getting used to having A.B in A, so there is something else in A would use A.B.
And C++ people is kind of #include everything, it feels like copy and paste everything into a single file and compile it. There are just files and includes.
Julia’s system is looking similar to C++20’s module system, which is not used by C++ world yet. Plus a package system.
In practice, after reading several matured Julia project, I feel like it’s more of old C++ way for most Julia packages. People just don’t use submodule, their package just has one single module which include all jl files within it. They keep things simple within a package so that any complicated dependencies problem can be handled by
Even when they do use submodule, like there is CUBLAS within
CUDA.jl, it’s not like how people from python would think of, where they have something in CUDA.jl which require the submodule CUBLAS, but actually the submodule CUBLAS is quite independent, which using …CUDA, and CUDA would include CUBLAS and export it.
It’s like there is A.B, but it’s just feels like a independent package(actually a module) written in A, but A doesn’t use B at all, it just export it. And everything that is used in A are just files getting included.
This how people’s think A.B is where the source of the confusing for people coming from python.
For example python people would put utils.jl as a module, and it’s feels very bad to have to
include("utils.jl") and then
using .Utils, and there maybe several places which use it, so there will be files been included several times.
But every package I saw for Julia, they just have utils.jl as file, not as module, and include(“util.jl”) at the top of the main module.
To me I feel like there is some redundancy to have file/module/package as 3 independent thing, it gives some people freedom but it gives others confusing. And in real world Julia packages, you don’t really see people using module concept efficiently. It’s more of people use files within package, and use package for real dependency problem.
I would suggest to clarify this mindset difference in the noteworthy-differences part of docs, where there is just one single line mentioned
The logical Julia program structure (Packages and Modules) is independent of the file strucutre (include for additional files), whereas the Python code structure is defined by directories (Packages) and files (Modules).
People from python don’t understand what it really means for package/file/module as independent things, and how to manage the code in such setting.