Spirit supports the creation of a default parser or a default generator from a given attribute type. It implements a minimal set of predefined mappings from different attribute types to parsers and generators (for a description of the predefined mappings see Additional Attribute Requirements for Parsers and Additional Attribute Requirements for Generators). The customization points described in this section (traits::create_parser and traits::create_generator) can be specialized to define additional mappings for custom data types.