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Visibility — Public vs Private Symbols

Nitpick uses a simple, binary visibility model. A symbol is either public (accessible from outside its defining module) or private (accessible only from within its defining module).

The pub Keyword

To make a symbol public, prefix its declaration with the pub keyword.

pub func:hello = int32() { pass 0i32; };
pub struct Point { int32:x; int32:y; };
pub mod utils { ... }

Applicable Declarations

The pub keyword can be applied to the following declarations: - func: (functions) - struct - enum - Rules - Type - const (module-level constants) - fixed (module-level immutable variables) - mod (modules)

Default Visibility (Private)

If the pub keyword is omitted, the symbol defaults to private. Private symbols cannot be imported or accessed by any other module.

// Private by default
func:internal_helper = int32() { pass 0i32; };

// Cannot be accessed by other modules via `use "this_file.npk".*`

Intra-Module Access

Within the same module (including the same file), all symbols are accessible to each other, regardless of whether they are marked pub or not. 

func:helper = int32() { pass 42i32; };

pub func:main_api = int32() {
    // Calling a private function within the same module is completely valid.
    int32:val = raw helper();
    pass val;
};

Cross-Module Access

When another module imports your file via use, only symbols explicitly marked as pub are exported and made available to the importer.

// file: math.npk
pub func:add = int32(int32:a, int32:b) { pass (a + b); };
func:sub = int32(int32:a, int32:b) { pass (a - b); }; // private

// file: main.npk
use "math.npk".*;

func:main = int32() {
    int32:x = raw add(1i32, 2i32);  // OK
    // int32:y = raw sub(2i32, 1i32); // Error: sub is private
    exit 0;
};

Error Messages

If you attempt to access or selectively import a private symbol from another module, the compiler will emit an error:

Symbol 'sub' is private and cannot be used outside its defining module.

To resolve this, ensure that the symbol is marked pub in its defining file.

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