Forem: Ryan Will

Pattern Match Struct's Name

Ryan Will — Tue, 21 Jan 2020 15:39:27 +0000

If we define the following struct.

defmodule StructTest do
    defstruct [:foo]
end

We can use pattern matching to capture the name of the struct in a variable.

%name{} = %StructTest{}
name # StructTest

The struct’s name could also be pattern matched in a function clause.

def print_name(%module_name{}) do
  IO.puts(module_name)
end

print_name(%StructTest{}) # StructTest

This is used in Elixir’s Access Module to dynamically call the fetch/2 function on a struct’s module.

Pattern match in with clause 🤯

Ryan Will — Wed, 15 Jan 2020 23:58:37 +0000

I had a problem where I needed to make sure a string was returned from a function that was part of a with clause. I thought, “You can’t pattern match here, right? That would just be too convenient.”

Turns out you totally can. Here’s an example from the docs.

users = %{"melany" => "guest", "bob" => :admin}

with {:ok, role} when not is_binary(role) <- Map.fetch(users, "bob") do
  {:ok, to_string(role)}
end

Using pattern matching to compare two strings

Ryan Will — Wed, 15 Jan 2020 12:56:53 +0000

Elixir’s pattern matching feature is the gift that keeps on giving. I love this neat trick to check if two strings are the same. It is an easy way to check if a password and password confirmation match.

def passwords_match?(password, password), do: true

def passwords_match?(_, _), do: false

passwords_match?("password", "password") # true
passwords_match?("password", "notpassword") # false

Spanish Software Blog or Podcast Recommendations

Ryan Will — Sun, 02 Dec 2018 15:16:41 +0000

I've been learning Spanish for a while and would like to find some software blogs or podcasts in Spanish to help with my comprehension. Anyone have any recommendations?