moai-lang-elixir

name	moai-lang-elixir
description	Elixir 1.17+ development specialist covering Phoenix 1.7, LiveView, Ecto, and OTP patterns. Use when developing real-time applications, distributed systems, or Phoenix projects.
version	1.0.0
category	language
modularized	true
user-invocable	false
updated	"2026-01-08T00:00:00.000Z"
status	active
allowed-tools	["Read","Grep","Glob","Bash","mcp__context7__resolve-library-id","mcp__context7__get-library-docs"]

Quick Reference (30 seconds)

Elixir 1.17+ Development Specialist - Phoenix 1.7, LiveView, Ecto, OTP patterns, and functional programming.

Auto-Triggers: .ex, .exs files, mix.exs, config/, Phoenix/LiveView discussions

Core Capabilities:

• Elixir 1.17: Pattern matching, pipes, protocols, behaviours, macros
• Phoenix 1.7: Controllers, LiveView, Channels, PubSub, Verified Routes
• Ecto: Schemas, Changesets, Queries, Migrations, Multi
• OTP: GenServer, Supervisor, Agent, Task, Registry
• ExUnit: Testing with setup, describe, async
• Mix: Build tool, tasks, releases
• Oban: Background job processing

Quick Patterns

Phoenix Controller:

defmodule MyAppWeb.UserController do
  use MyAppWeb, :controller

  alias MyApp.Accounts

  def show(conn, %{"id" => id}) do
    user = Accounts.get_user!(id)
    render(conn, :show, user: user)
  end

  def create(conn, %{"user" => user_params}) do
    case Accounts.create_user(user_params) do
      {:ok, user} ->
        conn
        |> put_flash(:info, "User created successfully.")
        |> redirect(to: ~p"/users/#{user}")

      {:error, %Ecto.Changeset{} = changeset} ->
        render(conn, :new, changeset: changeset)
    end
  end
end

Ecto Schema with Changeset:

defmodule MyApp.Accounts.User do
  use Ecto.Schema
  import Ecto.Changeset

  schema "users" do
    field :name, :string
    field :email, :string
    field :password_hash, :string
    field :password, :string, virtual: true

    timestamps()
  end

  def changeset(user, attrs) do
    user
    |> cast(attrs, [:name, :email, :password])
    |> validate_required([:name, :email, :password])
    |> validate_format(:email, ~r/@/)
    |> validate_length(:password, min: 8)
    |> unique_constraint(:email)
  end
end

GenServer Pattern:

defmodule MyApp.Counter do
  use GenServer

  def start_link(initial_value) do
    GenServer.start_link(__MODULE__, initial_value, name: __MODULE__)
  end

  def increment, do: GenServer.call(__MODULE__, :increment)
  def get_count, do: GenServer.call(__MODULE__, :get)

  @impl true
  def init(initial_value), do: {:ok, initial_value}

  @impl true
  def handle_call(:increment, _from, count), do: {:reply, count + 1, count + 1}
  def handle_call(:get, _from, count), do: {:reply, count, count}
end

---

Implementation Guide (5 minutes)

Elixir 1.17 Features

Pattern Matching Advanced:

def process_message(%{type: :email, to: to} = message) when is_binary(to) do
  send_email(message)
end

def process_message(%{type: :sms, phone: phone}) when byte_size(phone) == 10 do
  send_sms(phone)
end

def process_message(_), do: {:error, :invalid_message}