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defgeneric
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(lambda-macro ilisp (x)
'(lambda (&optional ,@(second x) &rest ignore) . ,(cddr x»)
Then the following example would define a function called new-list that
would use the lambda macro called ilisp:
(deffunction new-list ilisp (x y z)
(list x y z»
new-list's arguments are optional, and any extra arguments are ignored.
Examples:
(new-list 1 2) => (1 2 nil)
(new-list 1 2 3 4) -> (1 2 3)
I
defgeneric generic-function-name (argl arg2 ... ) options... Special Form
Defines a generic function named generic-function-name that accepts arguments
defined by (argl arg2 ... ), a lambda-list. The first argument, argl,
is required, unless the :function option is used to indicate otherwise. argl
represents the object that is supplied as the first argument to the generic
function. The flavor of argl determines which method is appropriate to
perform this generic function on the object. Any additional arguments
(arg2, and so on) are passed to the methods.
The arguments to defgeneric are displayed when you give the Arglist (M-X)
command or press c-sh-A while this generic function is current.
For example, to define a generic function total-fuel-supply that works on
instances of army and navy, and takes one argument (fuel-type) in addition
to the object itself, we might supply military-group as argl:
(defgeneric total-fuel-supply (military-group fuel-type)
"Returns today's total supply
of the given type of fuel
available to the given military group."
(:method-combination :sum»
The generic function is called as follows:
(total-fuel-supply blue-army ':gas)
The argument blue-army is known to be of flavor army. Therefore,
Flavors chooses the method that implements the total-fuel-supply generic
function on instances of the army flavor. That method takes only one argument,
fuel-type:
(defmethod (total-fuel-supply army) (fuel-type)
body of method)
The set of options for defgeneric are described elsewhere: See the section
"Options For defgeneric" in Symbolics Common Lisp: Language Concepts.