symbol-fstring

symbol-fstring is a Ruby extension that provide access to symbols internal string representations.

In Ruby many APIs tend to accept symbols, but regularly convert them to string internally. The typical example is ActiveSupport::HashWithIndifferentAccess, but there are plenty more.

The problem with this is that Symbol#to_s creates a new string every time it is invoked, and since it often happens in hotspots, it causes a lot of work for the garbage collector, and cause many identical strings to be kept in memory.

There was an attempt to make Symbol#to_s return its internal fstring for Ruby 2.7, but unfortunately it got reverted, instead Ruby 3.0 should have Symbol#name.

This gem backports the Symbol#name method for older rubies, and optionally allow to replace Symbol#to_s by Symbol#name.

Add this line to your application's Gemfile:

gem 'symbol-fstring'

And then execute:

$ bundle

Or install it yourself as:

$ gem install symbol-fstring

FString can be used in two ways.

By default this gem backport the Ruby 3.0 Symbol#name method.

If your application and your dependencies are compatible with it, you can change Symbol#to_s behavior globally with:

FString.patch_symbol!

Or you can also add it this way in your Gemfile:

gem 'symbol-fstring', require: 'fstring/all'

From benchmark/symbol-to_s

  Symbol#to_s (orig)     11.748M (± 1.7%) i/s -     58.786M in   5.005571s
 Symbol#name (patch)     18.067M (± 1.9%) i/s -     90.510M in   5.011549s

But there's also a reduced pressure on the garbage collector.

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/Shopify/symbol-fstring.

The gem is available as open source under the terms of the MIT License.