Enum ValType 

pub enum ValType {
    I32,
    I64,
    F32,
    F64,
    V128,
    Ref(RefType),
}

A list of all possible value types in WebAssembly.

Subtyping and Equality

ValType 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 ValType::matches and Val::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 ValType::eq method.

Variants

I32

Signed 32 bit integer.

I64

Signed 64 bit integer.

F32

Floating point 32 bit integer.

F64

Floating point 64 bit integer.

V128

A 128 bit number.

Ref(RefType)

An opaque reference to some type on the heap.

Implementations

impl ValType

pub const EXTERNREF: ValType

The externref type, aka (ref null extern).

pub const NULLEXTERNREF: ValType

The nullexternref type, aka (ref null noextern).

pub const FUNCREF: ValType

The funcref type, aka (ref null func).

pub const NULLFUNCREF: ValType

The nullfuncref type, aka (ref null nofunc).

pub const ANYREF: ValType

The anyref type, aka (ref null any).

pub const EQREF: ValType

The eqref type, aka (ref null eq).

pub const I31REF: ValType

The i31ref type, aka (ref null i31).

pub const ARRAYREF: ValType

The arrayref type, aka (ref null array).

pub const STRUCTREF: ValType

The structref type, aka (ref null struct).

pub const NULLREF: ValType

The nullref type, aka (ref null none).

pub const CONTREF: ValType

The contref type, aka (ref null cont).

pub const NULLCONTREF: ValType

The nullcontref type, aka. (ref null nocont).

pub const EXNREF: ValType

The exnref type, aka (ref null exn).

pub const NULLEXNREF: ValType

The nullexnref type, aka (ref null noexn).

pub fn is_num(&self) -> bool

Returns true if ValType matches any of the numeric types. (e.g. I32, I64, F32, F64).

pub fn is_i32(&self) -> bool

Is this the i32 type?

pub fn is_i64(&self) -> bool

Is this the i64 type?

pub fn is_f32(&self) -> bool

Is this the f32 type?

pub fn is_f64(&self) -> bool

Is this the f64 type?

pub fn is_v128(&self) -> bool

Is this the v128 type?

pub fn is_ref(&self) -> bool

Returns true if ValType is any kind of reference type.

pub fn is_funcref(&self) -> bool

Is this the funcref (aka (ref null func)) type?

pub fn is_externref(&self) -> bool

Is this the externref (aka (ref null extern)) type?

pub fn is_anyref(&self) -> bool

Is this the anyref (aka (ref null any)) type?

pub fn is_contref(&self) -> bool

Is this the contref (aka (ref null cont)) type?

pub fn as_ref(&self) -> Option<&RefType>

Get the underlying reference type, if this value type is a reference type.

pub fn unwrap_ref(&self) -> &RefType

Get the underlying reference type, panicking if this value type is not a reference type.

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

Does this value type match the other type?

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

Panics

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

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

Is value type a precisely equal to value type b?

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

Panics

Panics if either type is associated with a different engine.

pub fn default_value(&self) -> Option<Val>

Construct a default value. Returns None for non-nullable Ref types, which have no default.

Trait Implementations

impl Clone for ValType

fn clone(&self) -> ValType

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ValType

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

Formats the value using the given formatter.

impl Display for ValType

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

Formats the value using the given formatter.

impl From<RefType> for ValType

fn from(r: RefType) -> ValType

Converts to this type from the input type.

impl From<ValType> for StorageType

fn from(v: ValType) -> StorageType

Converts to this type from the input type.

impl Hash for ValType

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 WasmType for ValType

fn kind(&self) -> WasmTypeKind

Returns the WasmTypeKind of this type.

fn tuple_element_types(&self) -> Box<dyn Iterator<Item = ValType> + '_>

Returns an iterator of the tuple’s field Types. The iterator will be empty iff self is not a tuple type.

fn list_element_type(&self) -> Option<Self>

Returns the list element type or None if self is not a list type.

fn record_fields(&self) -> Box<dyn Iterator<Item = (Cow<'_, str>, Self)> + '_>

Returns an iterator of the record’s field names and Types. The iterator will be empty iff self is not a record type.

fn variant_cases( &self, ) -> Box<dyn Iterator<Item = (Cow<'_, str>, Option<Self>)> + '_>

Returns an iterator of the variant’s case names and optional payload Types. The iterator will be empty iff self is not a tuple type.

fn enum_cases(&self) -> Box<dyn Iterator<Item = Cow<'_, str>> + '_>

Returns an iterator of the enum’s case names. The iterator will be empty iff self is not an enum type.

fn option_some_type(&self) -> Option<Self>

Returns the option’s “some” type or None if self is not an option type.

fn result_types(&self) -> Option<(Option<Self>, Option<Self>)>

Returns the result’s optional “ok” and “err” Types or None if self is not a result type.

fn flags_names(&self) -> Box<dyn Iterator<Item = Cow<'_, str>> + '_>

Returns an iterator of the flags’ names. The iterator will be empty iff self is not a flags type.