Pass in an Elixir module or list of Elixir modules that implement defhost calls to generate imports for WebAssembly to be passed in when loading a WebAssembly module into the VM

Usage

When using a single module to define imports:

WaspVM.HostFunction.create_imports(Module1)

Functions will be accessible in the WebAssembly module as:

(import "Module1" "function_name")

When using multiple modules to define imports:

WaspVM.HostFunction.create_imports([Module1, Module2, Module3])

Functions will be accessible in the WebAssembly module as:

(import "Module1" "function_name")
(import "Module2" "function_name")
(import "Module3" "function_name")

Defines a host function that can be passed in to the VM using create_imports/1

Will use the name of the module that it's defined in as the name of the corresponding WebAssembly module that this host function can be imported from. fname can be a string or an atom. A variable called ctx is available within the context of the macro body as a pointer to VM state, to be used with functions defined in WaspVM.HostFunction.API.

Usage

Create an Elixir module that will be used to import host functions into WebAssembly:

defmodule Math do
  use WaspVM.HostFunction

  defhost add(a, b) do
    a + b
  end
end

Somewhere in your app:

defmodule MyWaspApp do
  def start do
    {:ok, pid} = WaspVM.start()

    imports = WaspVM.HostFunction.create_imports(Math)

    WaspVM.load_file(pid, "path/to/wasm/file.wasm", imports)
  end
end

In the above "path/to/wasm/file.wasm", the host function can now be imported:

(import "Math" "add" (func (param i32 i32) (result i32)))

Note that the Elixir module name was used to define the WebAssembly module name that's being used for the import.