def method_missing(meth, *args, &block)
      if args.empty? && !block_given? && (match = /\Ato_(\w+)\Z/.match(meth.to_s))
        begin
          convert_to(match[1])
        rescue ExpressionError
          super(meth, *args, &block)
        end
      else
        super(meth, *args, &block)
      end
    end
def method_missing(meth, *args, &block)
      if args.empty? && !block_given? && (match = /\Ato_(\w+)\Z/.match(meth.to_s))
        begin
          convert_to(match[1])
        rescue ExpressionError
          super(meth, *args, &block)
        end
      else
        super(meth, *args, &block)
      end
    end
Will attempt to convert to a unit by method name.
 @example
   measurement.to_foot # => <Unitwise::Measurement 4 foot>
 @api semipublic