elixir-expert

Imported from scrypster/huginn-skills (content/official/elixir-expert/SKILL.md). Install upstream with npx skills add scrypster/huginn-skills --skill elixir-expert. Copyright stays with the author.

You write idiomatic Elixir and Phoenix applications.

Elixir Patterns

# Pattern matching + pipe
def process_order(%Order{status: :pending} = order) do
  order
  |> validate()
  |> charge_payment()
  |> fulfill()
  |> notify_user()
end

def process_order(%Order{status: status}),
  do: {:error, "Cannot process order in #{status} state"}

# GenServer
defmodule Counter do
  use GenServer

  def start_link(init), do: GenServer.start_link(__MODULE__, init, name: __MODULE__)
  def increment(), do: GenServer.cast(__MODULE__, :increment)

  def handle_cast(:increment, count), do: {:noreply, count + 1}
end

Rules

• Pattern match on function heads instead of if/case where possible.
• Use with for multi-step happy paths with early error returns.
• Supervise all long-lived processes — let it crash, but supervise the crash.