Skip to content

5. Modules and imports

Once your program is more than one file, you’ll split it into modules and import what you need.

A tiny multi-file project

Create a folder:

my_project/
├── main.incn
└── strings.incn

strings.incn:

pub def shout(s: str) -> str:
    return s.strip().upper()

main.incn:

from strings import shout

def main() -> None:
    println(shout("  hello  "))

Run from my_project/:

incan run main.incn

Visibility: exporting with pub

By default, definitions are module-private (only usable inside the same .incn file). Prefix a declaration with pub to export it so other modules can import it.

Coming from Python?

In Python, most top-level definitions are effectively importable. In Incan, you typically make the intended “public API” of a module explicit with pub.

For more detail on pub (including how it affects model/class fields), see: Models & Classes.

Import styles

Incan supports two styles you can mix:

# Python-style
from strings import shout

# Rust-style
import strings::shout

The reference documents how parent/root paths work:

  • Parent: .. (Python-style) or super:: (Rust-style)
  • Project root: crate

See: Imports and modules (reference).

Try it

  1. Add another function in strings.incn (for example whisper).
  2. Mark it pub and import it into main.incn.
  3. Call both functions.
One possible solution 
# strings.incn
pub def shout(s: str) -> str:
    return s.strip().upper()

pub def whisper(s: str) -> str:
    return s.strip().lower()

# main.incn
from strings import shout, whisper

def main() -> None:
    println(shout("  hello  "))    # outputs: HELLO
    println(whisper("  HELLO  "))  # outputs: hello

What to learn next

Next

Back: 4. Control flow

Next chapter: 6. Errors (Result/Option and ?)