|ext:define-info-type class type type-spec &optional default||[Macro]|
Define a new type of global information for class. The type is the symbol name of the type, default is the value for that type when it has not been set, and type-spec is a type-specifier which values of the type must satisfy. The default expression is evaluated each time the information is needed, with name bound to the name for which the information is being looked up. If the default evaluates to something with the second value true, then the second value of info will also be true.