Struct Tag 

pub struct Tag(/* private fields */);

A generic, cheap, and mostly unique identifier.

Usage

A tag is a hashed representation of some string key. Two tags are equal if their hash values are equal.

Tags are defined to be very cheap to create, copy, and compare. However, they do not guarantee uniqueness. In most application domains, the chance of tag collision within a single subsystem is very low.

Internally, tags are hashed using a 64-bit FNV-1a algorithm.

Example

use moonshine_tag::prelude::*;

tags! { A, pub B };

assert_eq!(A, A);
assert_ne!(A, B);

Implementations

impl Tag

pub const fn new(source: &str) -> Tag

Creates a new tag from a string key.

Example

use moonshine_tag::prelude::*;

tags! { A };

assert_eq!(Tag::new("A"), A);

pub const fn from_hash(hash: u64) -> Tag

Creates a new tag from a hash value.

pub const fn hash(&self) -> u64

Returns the hash value of this tag.

pub fn pretty_hash(&self) -> String

Returns a human-friendly representation of this tag’s hash.

This is a base31-encoded string representation of the tag’s hash value.

This is, on average, faster than resolve_name for human-friendly identification.

pub fn matches(&self, filter: &TagFilter) -> bool

Returns true if this tag matches the given TagFilter.

pub fn resolve_name(&self) -> Option<&'static str>

Resolves the name of this tag if it has been defined using the tags! macro.

Note that this function is very slow and should not be used in performance-critical code. It performs a linear search over all registered tags to find a match and it is mainly designed for debugging and editor purposes.

If performance is a concern, consider using pretty_hash or cache the result of this function. See iter_names for an iterator over all registered tag names.

Tags must be defined using the tags! macro to be registered.

pub fn pretty_name(&self) -> Cow<'static, str>

Returns the name of this tag if it has been defined using the tags! macro. Otherwise, it returns the pretty_hash as a fallback.

Use this when you just want to display the most human-friendly format of the tag and do not care for handling any errors due to unregistered tags.

See:

• Tag::resolve_name
• Tag::pretty_hash

pub fn iter_names() -> impl Iterator<Item = &'static str>

Returns an iterator over all registered tag names.

Tags must be defined using the tags! macro to be registered.

Trait Implementations

impl Clone for Tag

fn clone(&self) -> Tag

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Tag

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Tag

fn deserialize<__D>( __deserializer: __D, ) -> Result<Tag, <__D as Deserializer<'de>>::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl From<Tag> for Tags

fn from(tag: Tag) -> Tags

Converts to this type from the input type.

impl FromIterator<Tag> for Tags

fn from_iter<T>(iter: T) -> Tags

where T: IntoIterator<Item = Tag>,

Creates a value from an iterator.

impl FromReflect for Tag

fn from_reflect(reflect: &(dyn PartialReflect + 'static)) -> Option<Tag>

Constructs a concrete instance of Self from a reflected value.

fn take_from_reflect( reflect: Box<dyn PartialReflect>, ) -> Result<Self, Box<dyn PartialReflect>>

Attempts to downcast the given value to Self using, constructing the value using from_reflect if that fails.

impl FromWorld for Tag

fn from_world(_: &mut World) -> Tag

Creates Self using data from the given World.

impl GetTypeRegistration for Tag

fn get_type_registration() -> TypeRegistration

Returns the default TypeRegistration for this type.

fn register_type_dependencies(registry: &mut TypeRegistry)

Registers other types needed by this type.

impl Hash for Tag

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

where H: Hasher,

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 IntoIterator for Tag

type Item = Tag

The type of the elements being iterated over.

type IntoIter = Once<Tag>

Which kind of iterator are we turning this into?

fn into_iter(self) -> <Tag as IntoIterator>::IntoIter

Creates an iterator from a value.

impl Ord for Tag

fn cmp(&self, other: &Tag) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for Tag

fn eq(&self, other: &Tag) -> 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 PartialOrd for Tag

fn partial_cmp(&self, other: &Tag) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl PartialReflect for Tag

fn get_represented_type_info(&self) -> Option<&'static TypeInfo>

Returns the TypeInfo of the type represented by this value.

fn try_apply( &mut self, value: &(dyn PartialReflect + 'static), ) -> Result<(), ApplyError>

Tries to apply a reflected value to this value.

fn reflect_kind(&self) -> ReflectKind

Returns a zero-sized enumeration of “kinds” of type.

fn reflect_ref(&self) -> ReflectRef<'_>

Returns an immutable enumeration of “kinds” of type.

fn reflect_mut(&mut self) -> ReflectMut<'_>

Returns a mutable enumeration of “kinds” of type.

fn reflect_owned(self: Box<Tag>) -> ReflectOwned

Returns an owned enumeration of “kinds” of type.

fn try_into_reflect( self: Box<Tag>, ) -> Result<Box<dyn Reflect>, Box<dyn PartialReflect>>

Attempts to cast this type to a boxed, fully-reflected value.

fn try_as_reflect(&self) -> Option<&(dyn Reflect + 'static)>

Attempts to cast this type to a fully-reflected value.

fn try_as_reflect_mut(&mut self) -> Option<&mut (dyn Reflect + 'static)>

Attempts to cast this type to a mutable, fully-reflected value.

fn into_partial_reflect(self: Box<Tag>) -> Box<dyn PartialReflect>

Casts this type to a boxed, reflected value.

fn as_partial_reflect(&self) -> &(dyn PartialReflect + 'static)

Casts this type to a reflected value.

fn as_partial_reflect_mut(&mut self) -> &mut (dyn PartialReflect + 'static)

Casts this type to a mutable, reflected value.

fn reflect_hash(&self) -> Option<u64>

Returns a hash of the value (which includes the type).

fn reflect_partial_eq( &self, value: &(dyn PartialReflect + 'static), ) -> Option<bool>

Returns a “partial equality” comparison result.

fn reflect_clone(&self) -> Result<Box<dyn Reflect>, ReflectCloneError>

Attempts to clone Self using reflection.

fn apply(&mut self, value: &(dyn PartialReflect + 'static))

Applies a reflected value to this value.

fn to_dynamic(&self) -> Box<dyn PartialReflect>

Converts this reflected value into its dynamic representation based on its kind.

fn reflect_clone_and_take<T>(&self) -> Result<T, ReflectCloneError>

where T: 'static, Self: Sized + TypePath,

For a type implementing PartialReflect, combines reflect_clone and take in a useful fashion, automatically constructing an appropriate ReflectCloneError if the downcast fails.

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

Debug formatter for the value.

fn is_dynamic(&self) -> bool

Indicates whether or not this type is a dynamic type.

impl Reflect for Tag

fn into_any(self: Box<Tag>) -> Box<dyn Any>

Returns the value as a Box<dyn Any>.

fn as_any(&self) -> &(dyn Any + 'static)

Returns the value as a &dyn Any.

fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)

Returns the value as a &mut dyn Any.

fn into_reflect(self: Box<Tag>) -> Box<dyn Reflect>

Casts this type to a boxed, fully-reflected value.

fn as_reflect(&self) -> &(dyn Reflect + 'static)

Casts this type to a fully-reflected value.

fn as_reflect_mut(&mut self) -> &mut (dyn Reflect + 'static)

Casts this type to a mutable, fully-reflected value.

fn set(&mut self, value: Box<dyn Reflect>) -> Result<(), Box<dyn Reflect>>

Performs a type-checked assignment of a reflected value to this value.

impl Serialize for Tag

fn serialize<__S>( &self, __serializer: __S, ) -> Result<<__S as Serializer>::Ok, <__S as Serializer>::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl TupleStruct for Tag

fn field(&self, index: usize) -> Option<&(dyn PartialReflect + 'static)>

Returns a reference to the value of the field with index index as a &dyn Reflect.

fn field_mut( &mut self, index: usize, ) -> Option<&mut (dyn PartialReflect + 'static)>

Returns a mutable reference to the value of the field with index index as a &mut dyn Reflect.

fn field_len(&self) -> usize

Returns the number of fields in the tuple struct.

fn iter_fields(&self) -> TupleStructFieldIter<'_>

Returns an iterator over the values of the tuple struct’s fields.

fn to_dynamic_tuple_struct(&self) -> DynamicTupleStruct

Creates a new DynamicTupleStruct from this tuple struct.

fn get_represented_tuple_struct_info(&self) -> Option<&'static TupleStructInfo>

Will return None if TypeInfo is not available.

impl TypePath for Tag

fn type_path() -> &'static str

Returns the fully qualified path of the underlying type.

fn short_type_path() -> &'static str

Returns a short, pretty-print enabled path to the type.

fn type_ident() -> Option<&'static str>

Returns the name of the type, or None if it is anonymous.

fn crate_name() -> Option<&'static str>

Returns the name of the crate the type is in, or None if it is anonymous.

fn module_path() -> Option<&'static str>

Returns the path to the module the type is in, or None if it is anonymous.

impl Typed for Tag

fn type_info() -> &'static TypeInfo

Returns the compile-time info for the underlying type.

impl Copy for Tag

impl Eq for Tag

impl StructuralPartialEq for Tag