Struct GKMinmaxStrategist 

pub struct GKMinmaxStrategist { /* private fields */ }

Available on crate feature GKMinmaxStrategist only.

The Minmax Strategist is a generic AI that selects a game model update for a given player that maximises potential gain, while minimising potential loss. It does this by examining all of the updates available to the player in question, extrapolating the potential moves opposing players may take, projecting out maxLookAheadDepth number of turns. The selected update will result in the greatest potential gain, balanced against the potential gain of other players.

See also Apple’s documentation

Implementations

impl GKMinmaxStrategist

pub unsafe fn maxLookAheadDepth(&self) -> NSInteger

The maximum number of future turns that will be processed when searching for a move.

pub unsafe fn setMaxLookAheadDepth(&self, max_look_ahead_depth: NSInteger)

Setter for maxLookAheadDepth.

pub unsafe fn bestMoveForPlayer( &self, player: &ProtocolObject<dyn GKGameModelPlayer>, ) -> Option<Retained<ProtocolObject<dyn GKGameModelUpdate>>>

Available on crate feature GKGameModel only.

Selects the best move for the specified player. If randomSource is not nil, it will randomly select which move to use if there are one or more ties for the best. Returns nil if the player is invalid, the player is not a part of the game model, or the player has no valid moves available.

pub unsafe fn randomMoveForPlayer_fromNumberOfBestMoves( &self, player: &ProtocolObject<dyn GKGameModelPlayer>, num_moves_to_consider: NSInteger, ) -> Option<Retained<ProtocolObject<dyn GKGameModelUpdate>>>

Available on crate feature GKGameModel only.

Selects one move from the set of N best moves for the specified player, where N is equal to numMovesToConsider. If randomSource is nil, it will not randomly select, but will behave like bestMoveForPlayer and return the first best move. Returns nil if the player is invalid, the player is not a part of the game model, or the player has no valid moves available.

impl GKMinmaxStrategist

Methods declared on superclass NSObject.

pub unsafe fn init(this: Allocated<Self>) -> Retained<Self>

pub unsafe fn new() -> Retained<Self>

Methods from Deref<Target = NSObject>

pub fn doesNotRecognizeSelector(&self, sel: Sel) -> !

Handle messages the object doesn’t recognize.

See Apple’s documentation for details.

Methods from Deref<Target = AnyObject>

pub fn class(&self) -> &'static AnyClass

Dynamically find the class of this object.

Panics

May panic if the object is invalid (which may be the case for objects returned from unavailable init/new methods).

Example

Check that an instance of NSObject has the precise class NSObject.

use objc2::ClassType;
use objc2::runtime::NSObject;

let obj = NSObject::new();
assert_eq!(obj.class(), NSObject::class());

pub unsafe fn get_ivar<T>(&self, name: &str) -> &T

where T: Encode,

👎Deprecated: this is difficult to use correctly, use Ivar::load instead.

Use Ivar::load instead.

Safety

The object must have an instance variable with the given name, and it must be of type T.

See Ivar::load_ptr for details surrounding this.

pub fn downcast_ref<T>(&self) -> Option<&T>

where T: DowncastTarget,

Attempt to downcast the object to a class of type T.

This is the reference-variant. Use Retained::downcast if you want to convert a retained object to another type.

Mutable classes

Some classes have immutable and mutable variants, such as NSString and NSMutableString.

When some Objective-C API signature says it gives you an immutable class, it generally expects you to not mutate that, even though it may technically be mutable “under the hood”.

So using this method to convert a NSString to a NSMutableString, while not unsound, is generally frowned upon unless you created the string yourself, or the API explicitly documents the string to be mutable.

See Apple’s documentation on mutability and on isKindOfClass: for more details.

Generic classes

Objective-C generics are called “lightweight generics”, and that’s because they aren’t exposed in the runtime. This makes it impossible to safely downcast to generic collections, so this is disallowed by this method.

You can, however, safely downcast to generic collections where all the type-parameters are AnyObject.

Panics

This works internally by calling isKindOfClass:. That means that the object must have the instance method of that name, and an exception will be thrown (if CoreFoundation is linked) or the process will abort if that is not the case. In the vast majority of cases, you don’t need to worry about this, since both root objects NSObject and NSProxy implement this method.

Examples

Cast an NSString back and forth from NSObject.

use objc2::rc::Retained;
use objc2_foundation::{NSObject, NSString};

let obj: Retained<NSObject> = NSString::new().into_super();
let string = obj.downcast_ref::<NSString>().unwrap();
// Or with `downcast`, if we do not need the object afterwards
let string = obj.downcast::<NSString>().unwrap();

Try (and fail) to cast an NSObject to an NSString.

use objc2_foundation::{NSObject, NSString};

let obj = NSObject::new();
assert!(obj.downcast_ref::<NSString>().is_none());

Try to cast to an array of strings.

use objc2_foundation::{NSArray, NSObject, NSString};

let arr = NSArray::from_retained_slice(&[NSObject::new()]);
// This is invalid and doesn't type check.
let arr = arr.downcast_ref::<NSArray<NSString>>();

This fails to compile, since it would require enumerating over the array to ensure that each element is of the desired type, which is a performance pitfall.

Downcast when processing each element instead.

use objc2_foundation::{NSArray, NSObject, NSString};

let arr = NSArray::from_retained_slice(&[NSObject::new()]);

for elem in arr {
    if let Some(data) = elem.downcast_ref::<NSString>() {
        // handle `data`
    }
}

Trait Implementations

impl AsRef<AnyObject> for GKMinmaxStrategist

fn as_ref(&self) -> &AnyObject

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<GKMinmaxStrategist> for GKMinmaxStrategist

fn as_ref(&self) -> &Self

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<NSObject> for GKMinmaxStrategist

fn as_ref(&self) -> &NSObject

Converts this type into a shared reference of the (usually inferred) input type.

impl Borrow<AnyObject> for GKMinmaxStrategist

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for GKMinmaxStrategist

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for GKMinmaxStrategist

const NAME: &'static str = "GKMinmaxStrategist"

The name of the Objective-C class that this type represents.

type Super = NSObject

The superclass of this class.

type ThreadKind = <<GKMinmaxStrategist as ClassType>::Super as ClassType>::ThreadKind

Whether the type can be used from any thread, or from only the main thread.

fn class() -> &'static AnyClass

Get a reference to the Objective-C class that this type represents.

fn as_super(&self) -> &Self::Super

Get an immutable reference to the superclass.

impl Debug for GKMinmaxStrategist

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Deref for GKMinmaxStrategist

type Target = NSObject

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl GKStrategist for GKMinmaxStrategist

unsafe fn gameModel(&self) -> Option<Retained<ProtocolObject<dyn GKGameModel>>>

where Self: Sized + Message,

Available on crate features GKStrategist and GKGameModel only.

The game model that we wish to select updates for.

unsafe fn setGameModel( &self, game_model: Option<&ProtocolObject<dyn GKGameModel>>, )

where Self: Sized + Message,

Available on crate features GKStrategist and GKGameModel only.

Setter for gameModel.

unsafe fn randomSource(&self) -> Option<Retained<ProtocolObject<dyn GKRandom>>>

where Self: Sized + Message,

Available on crate features GKStrategist and GKRandomSource only.

A random source to use when breaking ties between equally-strong moves when calling bestMoveForPlayer or when selecting a random move when randomMoveForPlayer is called. If set to nil, bestMoveForPlayer and randomMoveForPlayer will simply return the first best move available.

unsafe fn setRandomSource( &self, random_source: Option<&ProtocolObject<dyn GKRandom>>, )

where Self: Sized + Message,

Available on crate features GKStrategist and GKRandomSource only.

Setter for randomSource.

unsafe fn bestMoveForActivePlayer( &self, ) -> Option<Retained<ProtocolObject<dyn GKGameModelUpdate>>>

where Self: Sized + Message,

Available on crate features GKStrategist and GKGameModel only.

impl Hash for GKMinmaxStrategist

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Message for GKMinmaxStrategist

fn retain(&self) -> Retained<Self>

where Self: Sized,

Increment the reference count of the receiver.

impl NSObjectProtocol for GKMinmaxStrategist

fn isEqual(&self, other: Option<&AnyObject>) -> bool

where Self: Sized + Message,

Check whether the object is equal to an arbitrary other object.

fn hash(&self) -> usize

where Self: Sized + Message,

An integer that can be used as a table address in a hash table structure.

fn isKindOfClass(&self, cls: &AnyClass) -> bool

where Self: Sized + Message,

Check if the object is an instance of the class, or one of its subclasses.

fn is_kind_of<T>(&self) -> bool

where T: ClassType, Self: Sized + Message,

👎Deprecated: use isKindOfClass directly, or cast your objects with AnyObject::downcast_ref

Check if the object is an instance of the class type, or one of its subclasses.

fn isMemberOfClass(&self, cls: &AnyClass) -> bool

where Self: Sized + Message,

Check if the object is an instance of a specific class, without checking subclasses.

fn respondsToSelector(&self, aSelector: Sel) -> bool

where Self: Sized + Message,

Check whether the object implements or inherits a method with the given selector.

fn conformsToProtocol(&self, aProtocol: &AnyProtocol) -> bool

where Self: Sized + Message,

Check whether the object conforms to a given protocol.

fn description(&self) -> Retained<NSObject>

where Self: Sized + Message,

A textual representation of the object.

fn debugDescription(&self) -> Retained<NSObject>

where Self: Sized + Message,

A textual representation of the object to use when debugging.

fn isProxy(&self) -> bool

where Self: Sized + Message,

Check whether the receiver is a subclass of the NSProxy root class instead of the usual NSObject.

fn retainCount(&self) -> usize

where Self: Sized + Message,

The reference count of the object.

impl PartialEq for GKMinmaxStrategist

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl RefEncode for GKMinmaxStrategist

const ENCODING_REF: Encoding = <NSObject as ::objc2::RefEncode>::ENCODING_REF

The Objective-C type-encoding for a reference of this type.

impl DowncastTarget for GKMinmaxStrategist

impl Eq for GKMinmaxStrategist