# `String#underscore` Ruby Extension

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`fast_underscore` is a simple C extension which provides a fast implementation of [Active Support's `String#underscore` method](http://api.rubyonrails.org/classes/String.html#method-i-underscore).

## Do I need this?

Maybe! Run a stack profiler like [`ruby-prof`](https://github.com/ruby-prof/ruby-prof). If `String#underscore` or `ActiveSupport::Inflector#underscore` is coming up near the top of the list, this gem might be for you! If not, you probably don't need it. Either way, your milage may vary depending on the type of strings on which you're calling `underscore`.

## Usage with Rails

`ActiveSupport::Inflector#underscore` is actually used significantly throughout the Rails boot process, so it's best to hook into that process early to get the best results. Place the following lines above the `require 'rails'` line in your `application.rb` file:

```ruby
require 'active_support'
require 'fast_underscore'
```

This will allow Rails to use the faster underscore method while it is booting, which is used for autoloading dependencies, as well as determining table names.

## Is it fast?

At last check, these were the benchmarks (obtained by running `bin/benchmark`):

```
Warming up --------------------------------------
       ActiveSupport     2.000  i/100ms
      FastUnderscore    64.000  i/100ms
Calculating -------------------------------------
       ActiveSupport     28.839  (± 6.9%) i/s -    144.000  in   5.019140s
      FastUnderscore    650.151  (± 7.7%) i/s -      3.264k in   5.056094s

Comparison:
      FastUnderscore:      650.2 i/s
       ActiveSupport:       28.8 i/s - 22.54x  slower
```

## Installation

Add this line to your application's Gemfile:

```ruby
gem 'fast_underscore'
```

And then execute:

    $ bundle

Or install it yourself as:

    $ gem install fast_underscore

## Development

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](https://rubygems.org).

## Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/kddeisz/fast_underscore.

## License

The gem is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).