elixir guard

In Elixir, guards are used to add constraints to function clauses. They allow you to specify conditions that must be met for a particular function clause to be selected and executed. Guards are defined using the when keyword followed by a Boolean expression. Here's an example of how guards can be used in Elixir:

defmodule Math do
  def add(a, b) when is_number(a) and is_number(b) do
    a + b

  def add(a, b) do
    IO.puts "Error: Both arguments must be numbers!"

IO.puts Math.add(1, 2)  # Output: 3
IO.puts Math.add(1, "two")  # Output: Error: Both arguments must be numbers!

In this example, the add/2 function has two clauses. The first clause is selected and executed when both a and b are numbers. The second clause, which includes a guard, is selected and executed when the arguments are not numbers.

Guards can include various conditions such as type checks (is_atom/1, is_binary/1, etc.), value comparisons (==, !=, etc.), and pattern matches (=, ^, etc.). You can combine multiple conditions using logical operators (and, or, not, etc.).

Using guards can help improve the readability and maintainability of your code by allowing you to define clear constraints on function inputs.