# Module `iota::dynamic_object_field` Similar to iota::dynamic_field, this module allows for the access of dynamic fields. But unlike, iota::dynamic_field the values bound to these dynamic fields _must_ be objects themselves. This allows for the objects to still exist within in storage, which may be important for external tools. The difference is otherwise not observable from within Move. - [Struct `Wrapper`](#iota_dynamic_object_field_Wrapper) - [Function `add`](#iota_dynamic_object_field_add) - [Function `borrow`](#iota_dynamic_object_field_borrow) - [Function `borrow_mut`](#iota_dynamic_object_field_borrow_mut) - [Function `remove`](#iota_dynamic_object_field_remove) - [Function `exists_`](#iota_dynamic_object_field_exists_) - [Function `exists_with_type`](#iota_dynamic_object_field_exists_with_type) - [Function `id`](#iota_dynamic_object_field_id) - [Function `internal_add`](#iota_dynamic_object_field_internal_add) - [Function `internal_borrow`](#iota_dynamic_object_field_internal_borrow) - [Function `internal_borrow_mut`](#iota_dynamic_object_field_internal_borrow_mut) - [Function `internal_remove`](#iota_dynamic_object_field_internal_remove) - [Function `internal_exists_with_type`](#iota_dynamic_object_field_internal_exists_with_type) - [Macro function `add_impl`](#iota_dynamic_object_field_add_impl) - [Macro function `borrow_impl`](#iota_dynamic_object_field_borrow_impl) - [Macro function `borrow_mut_impl`](#iota_dynamic_object_field_borrow_mut_impl) - [Macro function `remove_impl`](#iota_dynamic_object_field_remove_impl) - [Macro function `exists_with_type_impl`](#iota_dynamic_object_field_exists_with_type_impl)

use iota::address;
use iota::dynamic_field;
use iota::hex;
use iota::object;
use iota::tx_context;
use std::ascii;
use std::bcs;
use std::option;
use std::string;
use std::vector;

## Struct `Wrapper`

public struct Wrapper<Name> has copy, drop, store

Fields

name: Name

## Function `add` Adds a dynamic object field to the object object: &mut UID at field specified by name: Name. Aborts with EFieldAlreadyExists if the object already has that field with that name.

public fun add<Name: copy, drop, store, Value: key, store>(object: &mut iota::object::UID, name: Name, value: Value)

Implementation

public fun add<Name: copy + drop + store, Value: key + store>(
    // we use &mut UID in several spots for access control
    object: &mut UID,
    name: Name,
    value: Value,
) {
    add_impl!(object, name, value)
}

## Function `borrow` Immutably borrows the objects dynamic object field with the name specified by name: Name. Aborts with EFieldDoesNotExist if the object does not have a field with that name. Aborts with EFieldTypeMismatch if the field exists, but the value object does not have the specified type.

public fun borrow<Name: copy, drop, store, Value: key, store>(object: &iota::object::UID, name: Name): &Value

Implementation

public fun borrow<Name: copy + drop + store, Value: key + store>(object: &UID, name: Name): &Value {
    borrow_impl!(object, name)
}

## Function `borrow_mut` Mutably borrows the objects dynamic object field with the name specified by name: Name. Aborts with EFieldDoesNotExist if the object does not have a field with that name. Aborts with EFieldTypeMismatch if the field exists, but the value object does not have the specified type.

public fun borrow_mut<Name: copy, drop, store, Value: key, store>(object: &mut iota::object::UID, name: Name): &mut Value

Implementation

public fun borrow_mut<Name: copy + drop + store, Value: key + store>(
    object: &mut UID,
    name: Name,
): &mut Value {
    borrow_mut_impl!(object, name)
}

## Function `remove` Removes the objects dynamic object field with the name specified by name: Name and returns the bound object. Aborts with EFieldDoesNotExist if the object does not have a field with that name. Aborts with EFieldTypeMismatch if the field exists, but the value object does not have the specified type.

public fun remove<Name: copy, drop, store, Value: key, store>(object: &mut iota::object::UID, name: Name): Value

Implementation

public fun remove<Name: copy + drop + store, Value: key + store>(
    object: &mut UID,
    name: Name,
): Value {
    remove_impl!(object, name)
}

## Function `exists_` Returns true if and only if the object has a dynamic object field with the name specified by name: Name.

public fun exists_<Name: copy, drop, store>(object: &iota::object::UID, name: Name): bool

Implementation

public fun exists_<Name: copy + drop + store>(object: &UID, name: Name): bool {
    let key = Wrapper { name };
    field::exists_with_type<Wrapper<Name>, ID>(object, key)
}

## Function `exists_with_type` Returns true if and only if the object has a dynamic field with the name specified by name: Name with an assigned value of type Value.

public fun exists_with_type<Name: copy, drop, store, Value: key, store>(object: &iota::object::UID, name: Name): bool

Implementation

public fun exists_with_type<Name: copy + drop + store, Value: key + store>(
    object: &UID,
    name: Name,
): bool {
    exists_with_type_impl!<_, Value>(object, name)
}

## Function `id` Returns the ID of the object associated with the dynamic object field Returns none otherwise

public fun id<Name: copy, drop, store>(object: &iota::object::UID, name: Name): std::option::Option<iota::object::ID>

Implementation

public fun id<Name: copy + drop + store>(object: &UID, name: Name): Option<ID> {
    let key = Wrapper { name };
    if (!field::exists_with_type<Wrapper<Name>, ID>(object, key)) return option::none();
    let (_field, value_addr) = field::field_info<Wrapper<Name>>(object, key);
    option::some(value_addr.to_id())
}

## Function `internal_add`

public(package) fun internal_add<Name: copy, drop, store, Value: key>(object: &mut iota::object::UID, name: Name, value: Value)

Implementation

public(package) fun internal_add<Name: copy + drop + store, Value: key>(
    // we use &mut UID in several spots for access control
    object: &mut UID,
    name: Name,
    value: Value,
) {
    add_impl!(object, name, value)
}

## Function `internal_borrow`

public(package) fun internal_borrow<Name: copy, drop, store, Value: key>(object: &iota::object::UID, name: Name): &Value

Implementation

public(package) fun internal_borrow<Name: copy + drop + store, Value: key>(
    object: &UID,
    name: Name,
): &Value {
    borrow_impl!(object, name)
}

## Function `internal_borrow_mut`

public(package) fun internal_borrow_mut<Name: copy, drop, store, Value: key>(object: &mut iota::object::UID, name: Name): &mut Value

Implementation

public(package) fun internal_borrow_mut<Name: copy + drop + store, Value: key>(
    object: &mut UID,
    name: Name,
): &mut Value {
    borrow_mut_impl!(object, name)
}

## Function `internal_remove`

public(package) fun internal_remove<Name: copy, drop, store, Value: key>(object: &mut iota::object::UID, name: Name): Value

Implementation

public(package) fun internal_remove<Name: copy + drop + store, Value: key>(
    object: &mut UID,
    name: Name,
): Value {
    remove_impl!(object, name)
}

## Function `internal_exists_with_type`

public(package) fun internal_exists_with_type<Name: copy, drop, store, Value: key>(object: &iota::object::UID, name: Name): bool

Implementation

public(package) fun internal_exists_with_type<Name: copy + drop + store, Value: key>(
    object: &UID,
    name: Name,
): bool {
    exists_with_type_impl!<_, Value>(object, name)
}

## Macro function `add_impl`

macro fun add_impl<$Name: copy, drop, store, $Value: key>($object: &mut iota::object::UID, $name: $Name, $value: $Value)

Implementation

macro fun add_impl<$Name: copy + drop + store, $Value: key>(
    // we use &mut UID in several spots for access control
    $object: &mut UID,
    $name: $Name,
    $value: $Value,
) {
    let object = $object;
    let name = $name;
    let value = $value;
    let key = Wrapper { name };
    let id = object::id(&value);
    field::add(object, key, id);
    let (field, _) = field::field_info<Wrapper<$Name>>(object, key);
    add_child_object(field.to_address(), value);
}

## Macro function `borrow_impl`

macro fun borrow_impl<$Name: copy, drop, store, $Value: key>($object: &iota::object::UID, $name: $Name): &$Value

Implementation

macro fun borrow_impl<$Name: copy + drop + store, $Value: key>(
    $object: &UID,
    $name: $Name,
): &$Value {
    let object = $object;
    let name = $name;
    let key = Wrapper { name };
    let (field, value_id) = field::field_info<Wrapper<$Name>>(object, key);
    borrow_child_object<$Value>(field, value_id)
}

## Macro function `borrow_mut_impl`

macro fun borrow_mut_impl<$Name: copy, drop, store, $Value: key>($object: &mut iota::object::UID, $name: $Name): &mut $Value

Implementation

macro fun borrow_mut_impl<$Name: copy + drop + store, $Value: key>(
    $object: &mut UID,
    $name: $Name,
): &mut $Value {
    let object = $object;
    let name = $name;
    let key = Wrapper { name };
    let (field, value_id) = field::field_info_mut<Wrapper<$Name>>(object, key);
    borrow_child_object_mut<$Value>(field, value_id)
}

## Macro function `remove_impl`

macro fun remove_impl<$Name: copy, drop, store, $Value: key>($object: &mut iota::object::UID, $name: $Name): $Value

Implementation

macro fun remove_impl<$Name: copy + drop + store, $Value: key>(
    $object: &mut UID,
    $name: $Name,
): $Value {
    let object = $object;
    let name = $name;
    let key = Wrapper { name };
    let (field, value_id) = field::field_info<Wrapper<$Name>>(object, key);
    let value = remove_child_object<$Value>(field.to_address(), value_id);
    field::remove<Wrapper<$Name>, ID>(object, key);
    value
}

## Macro function `exists_with_type_impl`

macro fun exists_with_type_impl<$Name: copy, drop, store, $Value: key>($object: &iota::object::UID, $name: $Name): bool

Implementation

macro fun exists_with_type_impl<$Name: copy + drop + store, $Value: key>(
    $object: &UID,
    $name: $Name,
): bool {
    let object = $object;
    let name = $name;
    let key = Wrapper { name };
    if (!field::exists_with_type<Wrapper<$Name>, ID>(object, key)) return false;
    let (field, value_id) = field::field_info<Wrapper<$Name>>(object, key);
    field::has_child_object_with_ty<$Value>(field.to_address(), value_id)
}