# 10. Modules & Packages

## import — split code across files
`import "file.st";` runs another file's top-level definitions (functions, classes,
stencils, variables) so you can use them.

`mathx.st`:
```stencil
func square(x) { return x * x; }
func cube(x) { return x * x * x; }
class Counter {
    func init() { this.n = 0; }
    func tick() { this.n = this.n + 1; return this.n; }
}
```
`main.st` (same folder):
```stencil
import "mathx.st";
print(square(6));   // 36
let c = Counter();
c.tick();
print(c.tick());    // 2
```
Paths are resolved relative to the importing file. Imports are de-duplicated, so
importing the same file twice is safe.

## Packages — install reusable modules
A project can declare dependencies in `stencil.json`:
```json
{
  "name": "myapp",
  "version": "0.1.0",
  "dependencies": {
    "greet": { "path": "../greetlib" },
    "utils": { "git": "https://github.com/user/utils" }
  }
}
```
- `path` — a local folder
- `git` — a git repository (cloned with git)

Install them:
```
stencil install
```
This copies/clones each dependency into `stencil_modules/`. Then import by name:
```stencil
import "greet";     // resolves to stencil_modules/greet/main.st (or greet.st)
print(selamla("World"));
```

## Starting a new package
```
stencil init        # creates a starter stencil.json
```

## Resolution order for `import "name"`
1. A file at that path relative to the current file (`import "lib/util.st"`).
2. For a bare name: `stencil_modules/name.st`, then `stencil_modules/name/main.st`,
   then `stencil_modules/name/name.st` — searching up parent folders.

Next: [Standard Library](11_standard_library.md)