lib/formula.rb
def type(method)
      if @object.respond_to?(:has_attribute?) && @object.has_attribute?(method)
        column = @object.column_for_attribute(method) if @object.respond_to?(:column_for_attribute)
        return column.type if column
      end
    end
def type(method)
      if @object.respond_to?(:has_attribute?) && @object.has_attribute?(method)
        column = @object.column_for_attribute(method) if @object.respond_to?(:column_for_attribute)
        return column.type if column
      end
    end
Introspection on the column to determine how to render a method. The method is used to
 identify a method type (if the method corresponds to a column)

 Returns:

 * :text     - for columns of type 'text'
 * :string   - for columns of type 'string'
 * :integer  - for columns of type 'integer'
 * :float    - for columns of type 'float'
 * :decimal  - for columns of type 'decimal'
 * :datetime - for columns of type 'datetime'
 * :date     - for columns of type 'date'
 * :time     - for columns of type 'time'
 * nil       - for unkown columns