Struct wasmer_ruby::Wasmer::Instance

pub struct Instance;

A WebAssembly instance is a stateful, executable instance of a WebAssembly Module.

Instance objects contain all the exported WebAssembly functions, memories, tables and globals that allow interacting with WebAssembly.

Specification: https://webassembly.github.io/spec/core/exec/runtime.html#module-instances

Examples

Example without an import object. The following creates a module with a sum exported function that sum two integers.

module_ = Wasmer::Module.new(
  Wasmer::Store.new,
  (<<~WAST)
  (module
    (type (func (param i32 i32) (result i32)))
    (func (type 0)
      local.get 0
      local.get 1
      i32.add)
    (export "sum" (func 0)))
  WAST
)
instance = Wasmer::Instance.new module_, nil

assert { instance.exports.sum.(1, 2) == 3 }

Example with an import object. The following creates a module that (i) imports a sum function from the math namespace, and (ii) exports an add_one function that adds 1 to any given integer (by using the math.sum function).

def sum(x, y)
  x + y
end

store = Wasmer::Store.new
module_ = Wasmer::Module.new(
  store,
  (<<~WAST)
  (module
    (import "math" "sum" (func $sum (param i32 i32) (result i32)))
    (func (export "add_one") (param i32) (result i32)
      local.get 0
      i32.const 1
      call $sum))
  WAST
)

import_object = Wasmer::ImportObject.new
import_object.register(
  "math",
  {
    :sum => Wasmer::Function.new(
       store,
       method(:sum),
       Wasmer::FunctionType.new([Wasmer::Type::I32, Wasmer::Type::I32], [Wasmer::Type::I32])
    )
  }
)

instance = Wasmer::Instance.new module_, import_object

assert { instance.exports.add_one.(1) == 2 }

Implementations

impl Instance

pub fn new(module: Module, import_object: ImportObject) -> Self

Creates a new Instance.

pub fn exports(&self) -> Exports

Returns all the exported entities.