Modules
Noir's module system follows the same convention as the newer version of Rust's module system.
Purpose of Modules
Modules are used to organize files. Without modules all of your code would need to live in a single file. In Noir, the compiler does not automatically scan all of your files to detect modules. This must be done explicitly by the developer.
Examples
Importing a module in the crate root
Filename : src/main.nr
mod foo;
fn main() {
foo::hello_world();
}
Filename : src/foo.nr
fn from_foo() {}
In the above snippet, the crate root is the src/main.nr
file. The compiler sees the module
declaration mod foo
which prompts it to look for a foo.nr file.
Visually this module hierarchy looks like the following :
crate
├── main
│
└── foo
└── from_foo
Importing a module throughout the tree
All modules are accessible from the crate::
namespace.
crate
├── bar
├── foo
└── main
In the above snippet, if bar
would like to use functions in foo
, it can do so by use crate::foo::function_name
.
Sub-modules
Filename : src/main.nr
mod foo;
fn main() {
foo::from_foo();
}
Filename : src/foo.nr
mod bar;
fn from_foo() {}
Filename : src/foo/bar.nr
fn from_bar() {}
In the above snippet, we have added an extra module to the module tree; bar
. bar
is a submodule
of foo
hence we declare bar in foo.nr
with mod bar
. Since foo
is not the crate root, the
compiler looks for the file associated with the bar
module in src/foo/bar.nr
Visually the module hierarchy looks as follows:
crate
├── main
│
└── foo
├── from_foo
└── bar
└── from_bar