6.5.8 Compound Presentation Types

The following compound presentation types are provided because they implement some common idioms.

token-or-type

Arguments: tokens type

Summary: A compound type that is used to select one of a set of special tokens, or an object of type type . tokens is anything that can be used as the sequence parameter to member-alist ; typically it is a list of symbols.

null-or-type

Arguments: type

Summary: A compound type that is used to select nil , whose printed representation is the special token "None," or an object of type type.

type-or-string

Arguments: type

Summary: A compound type that is used to select an object of type type or an arbitrary string, for example: (clim:type-or-string integer) . Any input that accept cannot parse as the representation of an object of type type is returned as a string.