# File lib/versionomy/format/delimiter.rb, line 471
        def field(name_, opts_={}, &block_)
          name_ = name_.to_sym
          field_ = @schema.field_named(name_)
          if !field_
            raise Errors::FormatCreationError, "Unknown field name #{name_.inspect}"
          end
          @field_handlers[name_] = Delimiter::FieldHandler.new(field_, opts_, &block_)
        end