Is there an approved way to add or register a new ARel visitor without
adding it to the ARel source? Looking at the some of the source
code<https://github.com/rails/arel/blob/master/lib/arel/visitors/to_sql.rb#L434-466>
it
appears that new visitors are just hard coded as a new methods or aliases.
The reason I'm asking is because I get "TypeError: Cannot visit ClassName"
when I override reader methods with some sort of composed object (similar
to Active Record's composed_of) and use that attribute in a uniqueness
validation.
Take the following for example:
class Cat < ActiveRecord::Base
validates :name, :uniqueness => { :scope => [:breed] }
def breed
CatBreed.new(super)
end
end
class CatBreed
def initialize(breed)
@breed = breed
end
def to_s
@breed
end
end
The above code will raise "TypeError: Cannot visit CatBreed" when I try to
create a new cat unless I add a visitor method to Arel::Visitors::ToSql
called visit_CatBreed:
class Arel::Visitors::ToSql
def visit_CatBreed(value)
quoted(value.to_s)
end
end
I'm hoping there is a better way to deal with this problem, either with a
less hacky ARel approach or something different all together.
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