View Source Orb: Write WebAssembly in Elixir, then run it anywhere

Orb is a DSL for WebAssembly with the full power of the Elixir language:

  • Function piping
  • Break problems into smaller modules and compose them together
  • Macros
  • Share code with the Hex package manager

Installation

If available in Hex, the package can be installed by adding orb to your list of dependencies in mix.exs:

def deps do
  [
    {:orb, "~> 0.1.0"}
  ]
end

About

defmodule CalculateMean do
  use Orb

  I32.global(
    count: 0,
    tally: 0
  )

  wasm do
    func insert(element: I32) do
      @count = @count + 1
      @tally = @tally + element
    end

    func calculate_mean(), I32 do
      @tally / @count
    end
  end
end

Orb.to_wat(CalculateMean)
# """
# (module $CalculateMean
#   (global $count (mut i32) (i32.const 0))
#   (global $tally (mut i32) (i32.const 0))
#   (func $insert (export "insert") (param $element i32)
#     (i32.add (global.get $count) (i32.const 1))
#     (global.set $count)
#     (i32.add (global.get $tally) (local.get $element))
#     (global.set $tally)
#   )
#   (func $calculate_mean (export "calculate_mean") (result i32)
#     (i32.div_s (global.get $tally) (global.get $count))
#   )
# )
# """

Run with OrbWasmtime:

alias OrbWasmtime.Instance

# Run above example
inst = Instance.run(CalculateMean)
Instance.call(inst, :insert, 4)
Instance.call(inst, :insert, 5)
Instance.call(inst, :insert, 6)
assert Instance.call(inst, :calculate_mean) == 5

Project Goals

  • Write a HTML component and run it in:
    • Phoenix LiveView & dead views
    • In the browser using <wasm-html> custom element
  • State machines
  • Parsers
  • Formatters & string builders

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/orb.