anonymous

Anonymous types are used to define a restricted structural definition of data, used to control the exact output structure.

The anonymous literal syntax &{...} is the preferred method for defining anonymous types:

&{
    field_1: 'type_def_1',
    field_2: 'type_def_2',
    // ...
}

As an alternative, the ano(..) function can be used. This is generally only useful when you need to construct the type definition dynamically at runtime using input or program logic.

Usage Example

In this example, an instance of the full User type is created, but the wrap method uses an anonymous type to ensure only specific fields (id, name, email) are returned, effectively hiding the sensitive password_hash.

// User type with three field:
set_type('User', {
    name: 'str',
    email: 'str',
    password_hash: 'str',
});

// Create an instance of "User"
.user = User{
    name: 'Jeroen van der Heijden',
    email: 'jeroen@cesbit.com',
    password_hash: 'SGVsbG8gVGhpbmdzREIhCg==',
};

// Output only the `name`, `user` and generated `id` attached to the user instance
.user.wrap(&{
    id: '#',
    name: 'str',
    email: 'str'
});

Possible return value in JSON format

{
    "id": 12345,
    "name": "Jeroen van der Heijden",
    "email": "jeroen@cesbit.com"
}

Complex Structures

Anonymous types support all standard type definitions, including nested structures, arrays, and enumerator references.

&{
    id: '#',
    checks: [{
        type: '*enum',  // exposes an enumerator type instance by its name
        options: {
            is_silent: 'bool',
            interval: 'int',
        },
    }],
}

For a comprehensive guide on all available type definitions and their syntax, please refer to the type overview page.

Related functions