temperature-converter.livemd

Orb Temperature Converter

Mix.install([
  {:orb, "~> 0.0.48"},
  {:wasmex, "~> 0.8.3"}
])

Define our temperature converter module using Orb

defmodule TemperatureConverter do
  use Orb

  Orb.I32.export_enum([:celsius, :fahrenheit])

  global do
    @mode 0
  end

  defw celsius_to_fahrenheit(celsius: F32), F32 do
    celsius * (9.0 / 5.0) + 32.0
  end

  defw fahrenheit_to_celsius(fahrenheit: F32), F32 do
    (fahrenheit - 32.0) * (5.0 / 9.0)
  end

  defw convert_temperature(temperature: F32), F32 do
    if @mode === @celsius do
      celsius_to_fahrenheit(temperature)
    else
      fahrenheit_to_celsius(temperature)
    end
  end

  defw set_mode(mode: I32) do
    @mode = mode
  end
end

We can compile this module to the WebAssembly text format

Orb.to_wat(TemperatureConverter)
|> IO.puts()

We can run the WebAssembly module in Elixir using Wasmex

{:ok, pid} = Wasmex.start_link(%{bytes: Orb.to_wat(TemperatureConverter)})

# Wasmex.call_function(pid, :fahrenheit_to_celsius, [72.0])

Wasmex.call_function(pid, :convert_temperature, [72.0])
|> IO.inspect()

Wasmex.call_function(pid, :set_mode, [1])

Wasmex.call_function(pid, :convert_temperature, [72.0])
|> IO.inspect()