GW supports organizing code into multiple files using the import keyword. This works similarly to the C/C++ preprocessor: the content of the imported file is directly substituted in place of the import statement.

import "filename.gw"

The path is relative to the file containing the import statement.

1. The FileReader scans the source code for lines starting with import.
2. When found, it resolves the path of the imported file.
3. It reads the content of that file and replaces the import line with it.
4. This process is recursive: imports inside imported files are also processed.
5. Circular Dependency Protection: The system keeps track of included files to prevent infinite loops (e.g., A imports B, B imports A). A file is only included once per compilation unit.

func square(x: Number) {
    return x * x;
}

import "math_utils.gw"

var result = square(5);
println(result); // Output: 25

Imports work with subdirectories as well:

project/
├── main.gw
└── lib/
    └── utils.gw

In main.gw:

import "lib/utils.gw"

In lib/utils.gw, you can import other files relative to lib/:

import "other_util.gw" // Looks for project/lib/other_util.gw