4 ms·

I couldn't find any actual examples on how to use the new frozen string literals. Lots of discussion in the link provided, but that's it.

• itafroma 11y ago
  The NEWS file defines what the pragma actually is,[1], but you'd use it like so: # frozen_string_literal: true str = 'foo' str << 'bar' This will now produce an error: # main.rb:3:in `<main>': can't modify frozen String (RuntimeError) It's equivalent to Ruby 2.1's String#freeze:[2] str = 'foo'.freeze str << 'bar' # main.rb:2:in `<main>': can't modify frozen String (RuntimeError) Except that it will affect all strings created after the pragma mark. You can also trigger this behavior globally with the --enable=frozen-string-literal option. [1]: https://github.com/ruby/ruby/blob/v2_3_0/NEWS#L17-L26 https://github.com/ruby/ruby/blob/v2_3_0/NEWS#L17-L26 [2]: http://ruby-doc.org/core-2.2.3/Object.html#method-i-freeze http://ruby-doc.org/core-2.2.3/Object.html#method-i-freeze