There are several ways to access slot values in an object. The naming and argument-order conventions are similar to those used for referencing vectors (see Vectors).
This macro sets the value behind slot to value in object. It returns value.
This macro sets the
:initformfor slot in class to value.
This allows the user to set both public and private defaults after the class has been constructed, and provides a way to configure the default behavior of packages built with classes (the same way
setq-defaultdoes for buffer-local variables).
For example, if a user wanted all
data-objects(see Building Classes) to inform a special object of his own devising when they changed, this can be arranged by simply executing this bit of code:(oset-default data-object reference (list my-special-object))
The following accessors are defined by CLOS to reference or modify slot values, and use the previously mentioned set/ref routines.
This function unbinds slot in object. Referencing an unbound slot can signal an error.
In OBJECT's slot, add item to the list of elements. Optional argument append indicates we need to append to the list. If item already exists in the list in slot, then it is not added. Comparison is done with equal through the member function call. If slot is unbound, bind it to the list containing item.
Bind spec-list lexically to slot values in object, and execute body. This establishes a lexical environment for referring to the slots in the instance named by the given slot-names as though they were variables. Within such a context the value of the slot can be specified by using its slot name, as if it were a lexically bound variable. Both setf and setq can be used to set the value of the slot.
spec-list is of a form similar to let. For example:((VAR1 SLOT1) SLOT2 SLOTN (VARN+1 SLOTN+1))
Where each var is the local variable given to the associated slot. A slot specified without a variable name is given a variable name of the same name as the slot.(defclass myclass () (x :initarg 1)) (setq mc (make-instance 'myclass)) (with-slots (x) mc x) => 1 (with-slots ((something x)) mc something) => 1