Elixir pattern matching makes you stop using if-clauses or exceptions

files.exs

defmodule Files do
 def run do
   process_file File.read("hello.txt")
 end

 def process_file({:ok, contents}) do
   IO.puts "File contents are here:"
   IO.puts contents
 end

 def process_file({:error, _}) do
   IO.puts "Could not open file :("
 end
end

Files.run

# Run it:
# $ elixir files.exs
# Could not open file :(
# $ touch hello.txt
# elixir files.exs
# File contents are here:
#