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Hashie Gains a Chainable Hash

Hashie, Intridea’s Hash Toolkit, is today with version 0.2.0 gaining a new member: the Clash.

A Clash is a “Chainable Lazy Hash” that allows you to construct a hash using method syntax. It is meant to be used in a similar way to the way that Rails 2.x’s named_scope or Arel’s query building work. Let’s start with an example:

require 'hashie/clash'  c = c.where(:abc => 'def').order(:created_at)  c == {:where => {:abc => 'def'}, :order => :created_at}

Pretty neat, right? But you can go beyond that. Clash also allows you to use bang method notation to create, dive into, and return from sub-hashes. Let me show you what I mean:

c = c.where!.abc('def').ghi(123)._end!.order(:created_at)  c == {:where => {:abc => 'def', :ghi => 123}, :order => :created_at}

By using a bang method, you automatically create a subhash that is then the subject of the chain, allowing you to create more keys on that subhash. Then, if you want to jump back up to the top-level hash, you simply call the _end! method to return up one level in the stack (thanks to jQuery for that particular inspiration).

While Clash is a very simple tool, we hope that it could eventually make its way into some of the new ORMs that are cropping up around NoSQL systems (such as MongoMapper) to provide the same kind of effortless chaining that has made ActiveRecord so easy to work with.


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