RQL for Ruby

This is a port of Kris Zyp's RQL (Resource Query Language) to Ruby.

Installation

$ gem install rql

The current parser uses ExecJS to run the RQL javascript parser. While ExecJS is generally good about using the best available javascript runtime, it's recommended that you use either:

To specify therubyracer runtime:

require 'rql'
require 'v8'

Rql.runtime = ExecJS::RubyRacerRuntime.new

To specify therubyrhino runtime under JRuby

require 'rql'
require 'rhino'

Rql.runtime = ExecJS::RubyRhinoRuntime.new

Usage

require 'rql'
query = Rql['id=5&name=foo']

data = [
     {"id" => 1, "name" => "foo"},
     {"id" => 5, "name" => "foo"}        
]

query.on(data) #=> [{"id" => 5, "name" => "foo"}]

Notes

You should keep the following in mind:

  • While the parsing of query strings should be identical to the javascript implementation, execution of the queries may not behave in exactly the same way.

  • Which query operations are supported, and how they behave is entirely dependent on the Evaluator class being used. Rql::Evaluator::Enumerable implements the evaluation behavior for Enumerable types.

  • Rql::Evaluator::Enumerable is probably broken, and is likely to change. That said, it's the best example of how Evaluators are currently implemented.