isabella232 / big_decimal_helper

Helpers for working with BigDecimal values

big_decimal_helper

Helpers for working with BigDecimals in Rails apps.

• Defines a #to_bd conversion protocol on Float, Fixnum, String, and NilClass to ease finger typing.
• Overrides BigDecimal#inspect to provide a more human-readable format:
  1234.56.to_bd # => #<BigDecimal: 1,234.56>
• Provides an ActiveRecord::Base.has_big_decimal_field macro to automatically convert various fields to BigDecimal.
• Provides some convenience methods for finding the min and max of a list that might possibly include NaN values. (This can cause some bugs that are extremely annoying to track down.)

A Note About Versions

As of 2.0.4, this gem will be published to rubygems.org. Earlier versions were published internally to LivingSocial. You're welcome to build them locally, if you're into that sort of thing.

Installation

Add this line to your application's Gemfile:

gem 'big_decimal_helper'

And then execute:

$ bundle

Or install it yourself as:

$ gem install big_decimal_helper

Usage

You'll be able to call #to_bd on any Fixnum, Float, String, or BigDecimal to ensure that you have a BigDecimal. nil.to_bd is also defined, and works similarly to nil.to_f or nil.to_i.

Also, if you have a field whose underlying type you can't change, but you want it to be automatically coerced to a BigDecimal, do this:

class Deal < ActiveRecord::Base
  has_big_decimal_field :final_revenue
end

This just calls .composed_of behind the scenes, but since I can never remember how to use that API, I wrapped it in a more intention-revealing macro.

(NOTE: This gem does not declare a dependency on ActiveRecord. If this gem loads before ActiveRecord does, that macro won't automatically appear. Should this happen to you, just add BigDecimalHelper.add_active_record_macro! to config/initializers/big_decimal_helper.rb in your Rails project.)

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Added some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request