WaspVM - Run WebAssembly in Elixir

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board = WaspVM.HostFunction.API.get_memory(ctx, "game_mem", 0, 9) Oooo awesome!

I like the post, easy to read, follow, and understand. :slight_smile:

As for WaspVM.HostFunction.API.get_memory/4 does that include the instruction pointer and all as well? I.E. if WASM calls ‘into’ an elixir function, can that elixir function serialize up the whole state then pick up again where it left off (assuming no other elixir functions are on the wasm stack, and probably some argument indicating whether it was just loaded or not)?

This variable is defined by the defhost macro, and is solely used as a reference that’s passed into the HostFunction API.

As for this, I’m really not a fan of magic variables, why not have the user prepend it to all defhost argument lists so it is explicitly passed in, thus:

defhost get_move_for_player(player) do

defhost draw_board do ... end

And so forth should actually be written like:

defhost get_move_for_player(vmctx, player) do

defhost draw_board(vmctx) do ... end

I always try to remember the Python tenant: Explicit is Better than Implicit :slight_smile:

Also, does this mean you can’t call the function from outside the WaspVM interpreter? Like what would you pass in then, the PID like this?

def run_game do
  # Start a fresh VM instance
  {:ok, pid} = WaspVM.start()
  WaspVM.load_file(pid, "priv/wasm/tic_tac_toe.wasm", imports)
  {:ok, gas, result} = WaspVM.execute(pid, "play")
  WaspVM.HostFunction.API.get_memory(pid, "game_mem", 0, 9)
end

Also, the calls return the gas, but is there a way to set a limit on how much gas is allowed to be used in a call before it just exceptions out or serializes/pauses its state or so for later resumption?

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