FGameplayTagQuery Struct Reference

An FGameplayTagQuery is a logical query that can be run against an FGameplayTagContainer. A query that succeeds is said to "match". Queries are logical expressions that can test the intersection properties of another tag container (all, any, or none), or the matching state of a set of sub-expressions (all, any, or none). This allows queries to be arbitrarily recursive and very expressive. For instance, if you wanted to test if a given tag container contained tags ((A && B) || (C)) && (!D), you would construct your query in the form ALL( ANY( ALL(A,B), ALL(C) ), NONE(D) ). More...

Public Member Functions
Functions
bool	IsEmpty () const
bool	Matches (FGameplayTagContainer Tags) const
FGameplayTagQuery &	opAssign (FGameplayTagQuery Other)
const FString &	GetDescription () const

Static Public Member Functions
Static Functions
static FGameplayTagQuery	MakeQuery_MatchAllTags (FGameplayTagContainer InTags)
static FGameplayTagQuery	MakeQuery_MatchNoTags (FGameplayTagContainer InTags)
static FGameplayTagQuery	MakeQuery_MatchTag (FGameplayTag InTag)
static FGameplayTagQuery	MakeQuery_MatchAnyTags (FGameplayTagContainer InTags)

Public Attributes
Hidden
TArray< FGameplayTag >	TagDictionary
	List of tags referenced by this entire query. Token stream stored indices into this list.
TArray< uint8 >	QueryTokenStream
	Stream representation of the actual hierarchical query.
FString	UserDescription
	User-provided string describing the query.
FString	AutoDescription
	Auto-generated string describing the query.
int	TokenStreamVersion
	Versioning for future token stream protocol changes. See EGameplayTagQueryStreamVersion.
Variables
const FString	Description

Static Public Attributes
Static Variables
static FGameplayTagQuery	EmptyQuery

Detailed Description

An FGameplayTagQuery is a logical query that can be run against an FGameplayTagContainer. A query that succeeds is said to "match". Queries are logical expressions that can test the intersection properties of another tag container (all, any, or none), or the matching state of a set of sub-expressions (all, any, or none). This allows queries to be arbitrarily recursive and very expressive. For instance, if you wanted to test if a given tag container contained tags ((A && B) || (C)) && (!D), you would construct your query in the form ALL( ANY( ALL(A,B), ALL(C) ), NONE(D) ).

You can expose the query structs to Blueprints and edit them with a custom editor, or you can construct them natively in code.

Example of how to build a query via code: FGameplayTagQuery Q; Q.BuildQuery( FGameplayTagQueryExpression() .AllTagsMatch() .AddTag(FGameplayTag::RequestGameplayTag(FName(TEXT("Animal.Mammal.Dog.Corgi")))) .AddTag(FGameplayTag::RequestGameplayTag(FName(TEXT("Plant.Tree.Spruce")))) );

Queries are internally represented as a byte stream that is memory-efficient and can be evaluated quickly at runtime. Note: these have an extensive details and graph pin customization for editing, so there is no need to expose the internals to Blueprints.

Member Function Documentation

GetDescription()

const FString & GetDescription

(

)

const

IsEmpty()

bool IsEmpty

(

)

const

MakeQuery_MatchAllTags()

FGameplayTagQuery MakeQuery_MatchAllTags ( FGameplayTagContainer InTags )

static

MakeQuery_MatchAnyTags()

FGameplayTagQuery MakeQuery_MatchAnyTags ( FGameplayTagContainer InTags )

static

MakeQuery_MatchNoTags()

FGameplayTagQuery MakeQuery_MatchNoTags ( FGameplayTagContainer InTags )

static

MakeQuery_MatchTag()

FGameplayTagQuery MakeQuery_MatchTag ( FGameplayTag InTag )

static

Matches()

bool Matches

(

FGameplayTagContainer

Tags

)

const

opAssign()

FGameplayTagQuery & opAssign

(

FGameplayTagQuery

Other

)

Member Data Documentation

AutoDescription

FString AutoDescription

Auto-generated string describing the query.

Description

const FString Description

EmptyQuery

FGameplayTagQuery EmptyQuery

static

QueryTokenStream

TArray<uint8> QueryTokenStream

Stream representation of the actual hierarchical query.

TagDictionary

TArray<FGameplayTag> TagDictionary

List of tags referenced by this entire query. Token stream stored indices into this list.

TokenStreamVersion

int TokenStreamVersion

Versioning for future token stream protocol changes. See EGameplayTagQueryStreamVersion.

UserDescription

FString UserDescription

User-provided string describing the query.