Struct FuncType

pub struct FuncType { /* private fields */ }

The type of a WebAssembly function.

WebAssembly functions can have 0 or more parameters and results.

Subtyping and Equality

FuncType does not implement Eq, because reference types have a subtyping relationship, and so 99.99% of the time you actually want to check whether one type matches (i.e. is a subtype of) another type. You can use the FuncType::matches and Func::matches_ty methods to perform these types of checks. If, however, you are in that 0.01% scenario where you need to check precise equality between types, you can use the FuncType::eq method.

Implementations

impl FuncType

pub fn new( engine: &Engine, params: impl IntoIterator<Item = ValType>, results: impl IntoIterator<Item = ValType>, ) -> FuncType

Creates a new function type from the given parameters and results.

The function type returned will represent a function which takes params as arguments and returns results when it is finished.

The resulting function type will be final and without a supertype.

Panics

Panics if any parameter or value type is not associated with the given engine.

pub fn with_finality_and_supertype( engine: &Engine, finality: Finality, supertype: Option<&FuncType>, params: impl IntoIterator<Item = ValType>, results: impl IntoIterator<Item = ValType>, ) -> Result<FuncType, Error>

Create a new function type with the given finality, supertype, parameter types, and result types.

Returns an error if the supertype is final, or if this function type does not match the supertype.

Panics

Panics if any parameter or value type is not associated with the given engine.

pub fn engine(&self) -> &Engine

Get the engine that this function type is associated with.

pub fn finality(&self) -> Finality

Get the finality of this function type.

pub fn supertype(&self) -> Option<FuncType>

Get the supertype of this function type, if any.

pub fn param(&self, i: usize) -> Option<ValType>

Get the ith parameter type.

Returns None if i is out of bounds.

pub fn params(&self) -> impl ExactSizeIterator

Returns the list of parameter types for this function.

pub fn result(&self, i: usize) -> Option<ValType>

Get the ith result type.

Returns None if i is out of bounds.

pub fn results(&self) -> impl ExactSizeIterator

Returns the list of result types for this function.

pub fn matches(&self, other: &FuncType) -> bool

Does this function type match the other function type?

That is, is this function type a subtype of the other function type?

Panics

Panics if either type is associated with a different engine from the other.

pub fn eq(a: &FuncType, b: &FuncType) -> bool

Is function type a precisely equal to function type b?

Returns false even if a is a subtype of b or vice versa, if they are not exactly the same function type.

Panics

Panics if either type is associated with a different engine from the other.

pub fn default_value(&self, store: impl AsContextMut) -> Result<Func, Error>

Construct a func which returns results of default value, if each result type has a default value.

Trait Implementations

impl Clone for FuncType

fn clone(&self) -> FuncType

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for FuncType

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

Formats the value using the given formatter.

impl Display for FuncType

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

Formats the value using the given formatter.

impl From<FuncType> for ExternType

fn from(ty: FuncType) -> ExternType

Converts to this type from the input type.

impl From<FuncType> for HeapType

fn from(f: FuncType) -> HeapType

Converts to this type from the input type.

impl Hash for FuncType

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.