Question

I have a hash value containing a variable:

module Categories
  module Services
    PHOTOGRAPHY_VIDEO = "9115"
  end
end

hash = {"CatId" => Categories::Services::PHOTOGRAPHY_VIDEO}

puts(hash["CatId"]) # This returns "9115" but how do I get the "Services" category?

I want to ask Ruby for the namespace of the variable ‘value’ of ‘CatId’ equal to ‘Services’. I want to do something like this:

def priced?
  (hash["CatId"]).unknown_method == Services
end

How do I obtain its namespace?

Answer 1

I don’t think this is possible. Given a value such as ‘9115’ there’s no way (other than an exhaustive search, which would only be practical if there were a small number total) of knowing what constants have been set to a particular video.

If you need to get at this information, I’d rethink what data you store – the value for the CatId key could be something with more information in it (eg a struct containing both the id and a textual description)