Bad idea of the week: ARel + DataMapper

gistfile1.rb

# Because I can't figure out how the fuck to get SQL out of datamapper itself
class PGEngine < Arel::Visitors::PostgreSQL
  attr_accessor :engine

  def initialize(engine)
    super
    self.engine = engine
  end

  def connection_pool
    self
  end

  def connection
    self
  end

  def tables
    []
  end

  def table_exists?(*args)
    true
  end

  def columns(name, description)
    model = DataMapper::Model.descendants.detect {|x| name == x.storage_name } || raise("Can't find model for #{name}")
    model.properties.map {|x|
      OpenStruct.new({name: x.name, type: x.class.to_s.split("::").last.downcase.to_sym})
    }
  end

  def with_connection
    yield(self)
  end

  def quote(value, column)
    "'#{value}'"
  end

  def quote_column_name(value)
    "'#{value}'"
  end

  def quote_table_name(value)
    "'#{value.underscore}'"
  end
end

posts = Arel::Table.new(:posts, :engine => PGEngine.new(bogus))
posts.project('*').where(pages[:author_id].eq(1)).to_sql