Modules

As your projects grow, you can split your code across several files and share pieces between them with export and import.

Exporting from a file

Put export in front of a function or variable to make it available to other files. Anything without export stays private to its own file.

// math.blm
export let GOLDEN = 1.618

export fn double(x) {
  return x * 2
}

// Private helper — not visible to other files.
fn secret() {
  return 42
}

Importing into another file

Use import { ... } from "..." to bring exported names into another file. List the names you want inside the braces. The path is the other file, written in quotes — the .blm extension is optional.

// main.blm
import { double, GOLDEN } from "./math"

print(double(21))   // 42
print(GOLDEN)       // 1.618

Paths starting with ./ are relative to the current file, so "./math" means "the file math.blm next to me".

Running it

Because modules read other files from disk, they run with the Bloom command-line tool rather than in the browser playground:

bloom run main.blm

This prints:

42
1.618

Rules to remember

• import and export must be at the top level of a file — not inside a function or loop.
• You can only import names that the other file actually exports. Importing something that isn't exported is an error.
• Two files cannot import each other (a circular import). If you need to share code between them, move it into a third file that both import.
• Each file is loaded once, even if several files import it.