Anonymous Functions

defmodule Account do
    def max_balance(amount) do
        "Max: #{amount}"
    end
end

We will use this syntax.

fn -> syntax

max_balance = fn(amount) -> "Max: #{amount}" end

max_balance.(500)

Account.run_transaction(100, 20, deposit)
Account.run_transaction(100, 20, withdrawal)

defmodule Account do
    def run_transaction(balanace, amount, transaction) do
        if balance <= 0 do
            "Cannot perform any transaction"
        else
            transaction.(balance, amount)
        end
    end
end

deposit = fn(balance, amount) -> balance + amount end
withdrawal = fn(balance, amount) -> balance - amount end


Account.run_transaction(1000, 20, withdrawal) -> 980
Account.run_transaction(1000, 20, deposit) - 1020
Account.run_transaction(0, 20, deposit)  -> "Cannot perform any transaction"

Pattern Matching in Anonymous Functions

account_transaction = fn
    (balance, amount, :deposit) -> balance + amount
    (balance, amount, :withdrawal) -> balance - amount
end

Anonymous Function Shorthand Syntax

deposit = fn(balance, amount) -> balance + amount end

deposit = &(&1 + &2)

Account.run_transaction(1000, 20, deposit)

Account.run_transaction(1000, 20, &(&1 + &2))

Enum.map([1, 2, 3, 4], &(&1 * 2))