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#5201 ✓wontfix
Grant Ammons

[patch] Named scope can accept other named scopes as an argument

Reported by Grant Ammons | July 26th, 2010 @ 10:16 PM | in 2.x

Hey all,

I've created a patch for Rails 2-3-stable that will allow named_scopes to use other defined named_scopes as arguments. This allows chaining named scopes within another named_scope.

For example:

class Post < ActiveRecord::Base
  named_scope :title_starts_with, lambda {|letter| {:conditions => ["title LIKE ?", letter + "%"]}}
  named_scope :title_starts_with_w, title_starts_with("W")
  named_scope :title_starts_with_w_limit_one, title_starts_with("W").limit(1)

What is this good for? It replicates the new arel-based query_interface, and could allow users using rails 2.3.9 (if included) to begin migrating their ActiveRecord queries early on, before Rails 3 is released into the wild.

An example of the power of this change -- I created a small gem called fake_arel that takes advantage of calling named scopes within other named scopes:

This gem implements all of the new rails 3 query interface finders using named scopes.

  Reply.where(:id => 1)"content,id").where("id > 1").order("id desc").limit(1)

Attached is a patch for 2-3-stable. I look forward to your opinions.

Comments and changes to this ticket

  • Andrea Campi

    Andrea Campi October 16th, 2010 @ 11:49 PM

    • Tag changed from patch named_scope named_scopes arel 2-3-stable 2.3.9 to 2-3-stable, named_scope, patch
  • Aditya Sanghi

    Aditya Sanghi October 17th, 2010 @ 05:55 AM

    • State changed from “new” to “wontfix”
    • Milestone set to 2.x
    • Assigned user set to “Santiago Pastorino”
    • Importance changed from “” to “Low”

    Grant, I doubt more features would be added to the 2.3x branch. Could your patch be integrated into your fake_are gem itself? Something like the rails_upgrade plugin.

    Marking the ticket wont fix but assigning to Santiago for his views. He might reopen if he feels otherwise.

  • Grant Ammons

    Grant Ammons October 17th, 2010 @ 03:20 PM

    This ticket can be closed. Because Rails 3 is out, I agree that this functionality does not need to be in ActiveRecord. If people would like to use an arel syntax in rails 2 applications, they should use fake_arel.

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