Predicate that checks whether FIELD is exempt from serialization.

Returns VALUE, unless it is the unset value, in which case it returns DEFAULT.

Predicate to check whether a 'maybe' value was explicitly provided.

Return a transducer for CONFIG that removes all maybe-type fields whose value is '%unset-marker.

Take CONFIGURATION-SYMBOL, the symbol corresponding to the name used when defining a configuration record with DEFINE-CONFIGURATION, and output the Texinfo documentation of its fields.

Same as string-join, but without join and string, returns a DELIMITER interposed LS. Support 'infix and 'suffix GRAMMAR values.