Modules

Every .basm file is a module. A module sees its own declarations, plus exactly what it imports, and nothing else.

Module names

A module is named by its path, with . in place of / and without the extension:

A leading . makes the path relative to the importing file’s directory. Without it, the path is looked up in the search path.

A first import

shapes.basm:

pub struct Point {
    pub x: int,
    pub y: int,
}

pub macro emit_point(p: Point) {
    @emit p
}

main.basm, in the same directory:

from .shapes import Point, emit_point

emit_point Point(1, 2)

Point { x: 1, y: 2 }

Every module has its own namespace

Two modules can declare the same name without conflict. A name always means what it meant in the file that wrote it: a macro imported from a library keeps using the library’s helpers, even if the importing file declares something with the same name.

Libraries and architecture packages

The standard library, std, is made of ordinary modules. So is every architecture: std.riscv.native is a module that imports std.riscv.impl, and std.x86_64.nasm builds on std.x86_64.intel. There’s no special kind of module for an instruction set.

In this chapter

• Imports: the forms of from ... import, and where modules are found.
• Visibility and re-exports: pub, pub from, and what happens when names collide.