Struct wasmtime::FuncType

pub struct FuncType { /* private fields */ }

Available on crate feature runtime only.

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 descriptor from the given parameters and results.

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

pub fn engine(&self) -> &Engine

Get the engine that this function type is associated with.

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<Item = ValType> + '_

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<Item = ValType> + '_

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.

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

Formats the value using the given formatter.

impl Display for FuncType

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

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) -> Self

Converts to this type from the input type.

impl Hash for FuncType

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.