Enum wai_bindgen_gen_core::Direction

pub enum Direction {
    Import,
    Export,
}

This is the direction from the user’s perspective. Are we importing functions to call, or defining functions and exporting them to be called?

This is only used outside of Generator implementations. Inside of Generator implementations, the Direction is translated to an AbiVariant instead. The ABI variant is usually the same as the Direction, but it’s different in the case of the Wasmtime host bindings:

In a wasm-calling-wasm use case, one wasm module would use the Import ABI, the other would use the Export ABI, and there would be an adapter layer between the two that translates from one ABI to the other.

But with wasm-calling-host, we don’t go through a separate adapter layer; the binding code we generate on the host side just does everything itself. So when the host is conceptually “exporting” a function to wasm, it uses the Import ABI so that wasm can also use the Import ABI and import it directly from the host.

These are all implementation details; from the user perspective, and from the perspective of everything outside of Generator implementations, export means I’m exporting functions to be called, and import means I’m importing functions that I’m going to call, in both wasm modules and host code. The enum here represents this user perspective.

Variants

Import

Export

Trait Implementations

impl Clone for Direction

fn clone(&self) -> Direction

Returns a copy of the value.

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

Performs copy-assignment from source.

impl PartialEq<Direction> for Direction

fn eq(&self, other: &Direction) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for Direction

impl Eq for Direction

impl StructuralEq for Direction

impl StructuralPartialEq for Direction