Module 0x1::option
This module defines the Option type and its methods to represent and handle an optional value.
- Struct
Option
- Constants
- Function
none
- Function
some
- Function
is_none
- Function
is_some
- Function
contains
- Function
borrow
- Function
borrow_with_default
- Function
get_with_default
- Function
fill
- Function
extract
- Function
borrow_mut
- Function
swap
- Function
swap_or_fill
- Function
destroy_with_default
- Function
destroy_some
- Function
destroy_none
- Function
to_vec
use 0x1::vector;
Struct Option
Abstraction of a value that may or may not be present. Implemented with a vector of size zero or one because Move bytecode does not have ADTs.
struct Option<Element> has copy, drop, store
Fields
Constants
The Option is in an invalid state for the operation attempted. The Option is Some while it should be None.
const EOPTION_IS_SET: u64 = 262144;
The Option is in an invalid state for the operation attempted. The Option is None while it should be Some.
const EOPTION_NOT_SET: u64 = 262145;
Function none
Return an empty Option
public fun none<Element>(): option::Option<Element>
Implementation
Function some
Return an Option containing e
public fun some<Element>(e: Element): option::Option<Element>
Implementation
Function is_none
Return true if t does not hold a value
public fun is_none<Element>(t: &option::Option<Element>): bool
Implementation
Function is_some
Return true if t holds a value
public fun is_some<Element>(t: &option::Option<Element>): bool
Implementation
Function contains
Return true if the value in t is equal to e_ref Always returns false if t does not hold a value
public fun contains<Element>(t: &option::Option<Element>, e_ref: &Element): bool
Implementation
Function borrow
Return an immutable reference to the value inside t Aborts if t does not hold a value
public fun borrow<Element>(t: &option::Option<Element>): &Element
Implementation
Function borrow_with_default
Return a reference to the value inside t if it holds one Return default_ref if t does not hold a value
public fun borrow_with_default<Element>(t: &option::Option<Element>, default_ref: &Element): &Element
Implementation
Function get_with_default
Return the value inside t if it holds one Return default if t does not hold a value
public fun get_with_default<Element: copy, drop>(t: &option::Option<Element>, default: Element): Element
Implementation
Function fill
Convert the none option t to a some option by adding e. Aborts if t already holds a value
public fun fill<Element>(t: &mut option::Option<Element>, e: Element)
Implementation
Function extract
Convert a some option to a none by removing and returning the value stored inside t Aborts if t does not hold a value
public fun extract<Element>(t: &mut option::Option<Element>): Element
Implementation
Function borrow_mut
Return a mutable reference to the value inside t Aborts if t does not hold a value
public fun borrow_mut<Element>(t: &mut option::Option<Element>): &mut Element
Implementation
Function swap
Swap the old value inside t with e and return the old value Aborts if t does not hold a value
public fun swap<Element>(t: &mut option::Option<Element>, e: Element): Element
Implementation
Function swap_or_fill
Swap the old value inside t with e and return the old value; or if there is no old value, fill it with e. Different from swap(), swap_or_fill() allows for t not holding a value.
public fun swap_or_fill<Element>(t: &mut option::Option<Element>, e: Element): option::Option<Element>
Implementation
Function destroy_with_default
Destroys t. If t holds a value, return it. Returns default otherwise
public fun destroy_with_default<Element: drop>(t: option::Option<Element>, default: Element): Element
Implementation
Function destroy_some
Unpack t and return its contents Aborts if t does not hold a value
public fun destroy_some<Element>(t: option::Option<Element>): Element
Implementation
Function destroy_none
Unpack t Aborts if t holds a value
public fun destroy_none<Element>(t: option::Option<Element>)
Implementation
Function to_vec
Convert t into a vector of length 1 if it is Some, and an empty vector otherwise
public fun to_vec<Element>(t: option::Option<Element>): vector<Element>