Question

Using a framework I need 2 ActiveRecord scopes:

scope :tagged_with, lambda { |tag| {:conditions => [" tags like ? ",  "% #{tag} %"] } }
scope :tagged_with_any, lambda { |tag_array | [HERE NEW IMPLEMENTATION] }

I want the second scope to be based on the first scope. If you would do it hard coded, you would do for a 2 element array:

lambda { | tag_array | tagged_with(tag_array[0]).tagged_with(tag_array[1]) }

which works, but how do I do it generic

lambda { | tag_array | tags.each { |t| tagged_with(t) } }

clearly doesn’t do the job.

Answer 1

Is this acceptable?

named_scope :tagged_with_all, lambda { |tag_array| tag_array.inject(self, :tagged_with) }

[edit] renamed to tagged_with_all since it’s what it really does. For a tagged_with_any, Vanilla named scopes do not implement OR-concatenations; concatenating ORs conditions “manually” from scopes is doable but a bit messy. Note that you have libraries like Arel or Metawhere.