eieio: Class Options
3.3 Class Options
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In the OPTIONS-AND-DOC arguments to ‘defclass’, the following class
options may be specified:
‘:documentation’
A documentation string for this class.
If an Emacs-style documentation string is also provided, then this
option is ignored. An Emacs-style documentation string is not
prefixed by the ‘:documentation’ tag, and appears after the list of
slots, and before the options.
‘:allow-nil-initform’
If this option is non-‘nil’, and the ‘:initform’ is ‘nil’, but the
‘:type’ is specifies something such as ‘string’ then allow this to
pass. The default is to have this option be off. This is
implemented as an alternative to unbound slots.
This options is specific to Emacs, and is not in the CLOS spec.
‘:abstract’
A class which is ‘:abstract’ cannot be instantiated, and instead is
used to define an interface which subclasses should implement.
This option is specific to Emacs, and is not in the CLOS spec.
‘:custom-groups’
This is a list of groups that can be customized within this class.
This slot is auto-generated when a class is created and need not be
specified. It can be retrieved with the ‘class-option’ command,
however, to see what groups are available.
This option is specific to Emacs, and is not in the CLOS spec.
‘:method-invocation-order’
This controls the order in which method resolution occurs for
‘:primary’ methods in cases of multiple inheritance. The order
affects which method is called first in a tree, and if
‘call-next-method’ is used, it controls the order in which the
stack of methods are run.
Valid values are:
‘:breadth-first’
Search for methods in the class hierarchy in breadth first
order. This is the default.
‘:depth-first’
Search for methods in the class hierarchy in a depth first
order.
‘:c3’
Searches for methods in a linearized way that most closely
matches what CLOS does when a monotonic class structure is
defined.
Method Invocation, for more on method invocation order.
‘:metaclass’
Unsupported CLOS option. Enables the use of a different base class
other than ‘standard-class’.
‘:default-initargs’
Unsupported CLOS option. Specifies a list of initargs to be used
when creating new objects. As far as I can tell, this duplicates
the function of ‘:initform’.
CLOS compatibility, for more details on CLOS tags versus
EIEIO-specific tags.
Info Catalog
eieio: Slot Options
eieio: Building Classes