Rust Strings compared to Ruby Strings

Let’s learn about Rust strings. As in plural. There are essentially two types. Um, what? You can’t be serious? Well, kinda.

Photo by Alina Grubnyak on Unsplash

Is this going to be one of those examples that demonstrates why Rust is hard to learn? No, not really. But, as simple as Strings are in other languages, they are a great gateway into the Rust ownership model, stack vs heap, etc… Before we get ahead of ourselves, let’s see some simple examples compared to Ruby.

In Ruby, we can use Strings as values for variables and constants. We’re going to use our Ruby project from the Getting Started post.

# lib/my_project_ruby.rb

module MyProjectRuby
  class Error < StandardError; end
  # Your code goes here...
  puts "hello world"
end

You can see we already use a String in the puts statement. The code “hello world” defines a String value. Let’s add some more examples.

# lib/my_project_ruby.rb

module MyProjectRuby
  class Error < StandardError; end
  
  NAME = "foo"
  puts NAME.class # => String

  substring = "this is a string".split(" ").last  
  puts substring.class # => String

  puts "hello world".class
end

If you run this file via ruby lib/my_project_ruby.rb from the project root, you will see:

String
String
String