elixir.md

Elixir Primer

Core Concepts

• Functional language built on Erlang VM (BEAM)
• Immutable data - values never change
• Pattern matching as primary control flow
• Process-oriented concurrency (not OS threads)
• Fault tolerance via supervision trees

Syntax Basics

# Functions
def add(a, b), do: a + b

# Anonymous functions
add = fn a, b -> a + b end

# Pipe operator
"hello" |> String.upcase() |> String.reverse()

# Pattern matching
[head | tail] = [1, 2, 3]  # head = 1, tail = [2, 3]

Data Types

• Atoms: :ok, :error (symbols)
• Tuples: {:ok, result}, {:error, reason}
• Lists: [1, 2, 3] (linked lists)
• Maps: %{key: "value"}
• Structs: %User{name: "John"}

Concurrency Model

• Processes: Lightweight (2KB), isolated memory
• Message passing: send(pid, message) and receive
• No shared state between processes
• OTP: Framework for building fault-tolerant apps

Key Paradigms

• "Let it crash" philosophy
• Supervisors restart failed processes
• GenServer for stateful processes
• Pattern matching for control flow
• Protocols for polymorphism

Project Structure

• Mix: Build tool
• Modules: Code organization units
• Behaviours: Interface definitions
• Applications: Standalone or composable units
• Umbrella projects: Multi-app projects