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Question concerning methods

Howdy,

    Now, I haven't found a legal way to get the lambda-list of a generic
    function. In Allegro4.1, it is in the slot "CLOS::PRETTY-ARGLIST", in
    Lucid, it is in the slot "CLOS::LAMBDA-LIST" of the generic function
    object. 

I believe most vendors are adhering to David Moon's Proposal for the
MetaObject protocal for introspection.  GENERIC-FUNCTION-LAMBDA-LIST
is the equivalent of CLOS::LAMBDA-LIST and is part of Lucid's
forthcoming 4.1 release.

Sincerely,

John S. Kern
Lucid, Inc.
Customer Support

================ copy of proposal =======================
Date: Sun, 4 Mar 90 18:28 EST
From: David A. Moon <Moon@STONY-BROOK.SCRC.Symbolics.COM>
Subject: Proposed de facto standard subset of metaobjects
To: Common-Lisp-Object-System@MCC.COM

. . . 

The full CLOS metaobject facility provides a model of the system that can be
used both for introspection (a program examining its own structure) and for
extension (changing the behavior of metaobjects and implementation of new
object-oriented languages within the CLOS framework).  What is being proposed
here is only introspection.  While extension is useful and needed, it is 
clearly more difficult and not as ready for standardization as introspection,
so it will have to wait until later.

. . .

For now we are only proposing names, not precise definitions of what they do.
The definitions will be necessary, but they are a lot of work so we'll do
that later, after we see whether it is possible to agree on the names.

At Symbolics we came up with three packages (COMMON-LISP, CLOS, and
CLOS-INTERNALS).  COMMON-LISP is the package whose contents is defined by
ANSI Common Lisp.  CLOS is the package that exports all the "standardized"
symbols of CLOS, not only the ones defined by ANSI Common Lisp but also some
others that make sense to standardize on in a de facto way.  The idea is that
a program can :USE CLOS in its DEFPACKAGE, or use CLOS: package prefixes
throughout the program, to get the CLOS facilities that one would expect to
be portable to other implementations.  The name and existence of the CLOS
package is part of the proposed de facto standard.  CLOS-INTERNALS exports
the things that we might want wizardly users and our own tools to use, but
that are not being proposed for standardization.  Things in CLOS-INTERNALS
are not necessarily compatible even among Symbolics' own various
implementations and are not being proposed as a standard.  There's no need
even to agree on the name of that package; indeed, Lucid does not use that
particular package name.

Exporting the ANSI Common Lisp standardized symbols of CLOS from the package
named CLOS facilitates using CLOS in programs that are otherwise written
using the CLtL dialect rather than the ANSI dialect.

I believe the policy we're working from can be succinctly stated as "exports
from the CLOS package are all and only those symbols which are the current
(draft proposed) ANSI standard CLOS or seem likely to be recommended for
future ANSI standardization."

The remainder of this message lists the proposed external symbols of the CLOS
package, in three parts.  The first part is a list of the extensions to
standardized CLOS being proposed at this time.  The second part is a list of
additional extensions that only apply to Common Lisps that support locatives.
That list is being proposed at this time, but does not apply to most Common
Lisp implementations; these symbols would only exist in implementations that
actually have locatives.  The third part is a list of the symbols in
standardized CLOS, for completeness.



NON-ANSI-STANDARD SYMBOLS EXPORTED BY THE CLOS PACKAGE:

  CLASS-DEFAULT-INITARGS                     CLOS generic function
  CLASS-DIRECT-DEFAULT-INITARGS              CLOS generic function
  CLASS-DIRECT-SLOTS                         CLOS generic function
  CLASS-DIRECT-SUBCLASSES                    CLOS generic function
  CLASS-DIRECT-SUPERCLASSES                  CLOS generic function
  CLASS-PRECEDENCE-LIST                      CLOS generic function
  CLASS-PROTOTYPE                            CLOS generic function
  CLASS-SLOTS                                CLOS generic function
  COMPUTE-EFFECTIVE-METHOD                   CLOS generic function
  FORWARD-REFERENCED-CLASS                   class name
  FUNCALLABLE-STANDARD-CLASS                 class name
  GENERIC-FUNCTION-ARGUMENT-PRECEDENCE-ORDER CLOS generic function
  GENERIC-FUNCTION-DECLARATIONS              CLOS generic function
  GENERIC-FUNCTION-INITIAL-METHODS           CLOS generic function
  GENERIC-FUNCTION-LAMBDA-LIST               CLOS generic function
  GENERIC-FUNCTION-METHOD-CLASS              CLOS generic function
  GENERIC-FUNCTION-METHOD-COMBINATION        CLOS generic function
  GENERIC-FUNCTION-METHODS                   CLOS generic function
  GENERIC-FUNCTION-NAME                      CLOS generic function
  METHOD-FUNCTION                            CLOS generic function
  METHOD-GENERIC-FUNCTION                    CLOS generic function
  METHOD-LAMBDA-LIST                         CLOS generic function
  METHOD-SLOT-NAME                           CLOS generic function
  METHOD-SPECIALIZERS                        CLOS generic function
  SLOT-BOUNDP-USING-CLASS                    CLOS generic function
  SLOT-DEFINITION                            class name
  SLOT-DEFINITION-ALLOCATION                 CLOS generic function
  SLOT-DEFINITION-INITARGS                   CLOS generic function
  SLOT-DEFINITION-INITFORM                   CLOS generic function
  SLOT-DEFINITION-INITFUNCTION               CLOS generic function
  SLOT-DEFINITION-NAME                       CLOS generic function
  SLOT-DEFINITION-READERS                    CLOS generic function
  SLOT-DEFINITION-TYPE                       CLOS generic function
  SLOT-DEFINITION-WRITERS                    CLOS generic function
  SLOT-EXISTS-P-USING-CLASS                  CLOS generic function
  SLOT-MAKUNBOUND-USING-CLASS                CLOS generic function
  SLOT-VALUE-USING-CLASS                     CLOS generic function, SETFable, LOCFable
  SPECIALIZER-DIRECT-GENERIC-FUNCTIONS       CLOS generic function
  SPECIALIZER-DIRECT-METHODS                 CLOS generic function
  STANDARD-ACCESSOR-METHOD                   class name
  STANDARD-READER-METHOD                     class name
  STANDARD-SLOT-DEFINITION                   class name
  STANDARD-WRITER-METHOD                     class name



Notes:

The CLASS-xxx accessors always work, no explicit "finalize" is required.
We're not sure whether this is a change from 89-003 or not.

Using SETF with any of these names not indicated to be SETFable should
signal an error.

The following symbols are exported from the CLOS package by both Symbolics and
Lucid, but are not being proposed for a standard at this time, for the reasons
given:

  CLASS-DIRECT-METHODS            use SPECIALIZER-DIRECT-METHODS
  CLASS-FINALIZED-P               not needed for introspection
  COMPUTE-CLASS-PRECEDENCE-LIST   use CLASS-PRECEDENCE-LIST

SPECIALIZER-DIRECT-METHODS is more general than CLASS-DIRECT-METHODS.
COMPUTE-CLASS-PRECEDENCE-LIST is needed for extension, where users
define new methods for it to implement different CPL rules, but for
introspection it is just a slower version of CLASS-PRECEDENCE-LIST.

Lucid's CLOS package exports several additional symbols as well:
LIST-ALL-CLASSES, TRACE-METHOD, UNDEFMETHOD, UNTRACE-METHOD.  These
are not being proposed for standardization right now.

Symbolics' CLOS package exports several additional symbols as well:
CLASS-DEFAULT-DIRECT-SUPERCLASSES, DIRECT-SLOT-DEFINITION,
EFFECTIVE-SLOT-DEFINITION, STANDARD-DIRECT-CLASS-SLOT-DEFINITION,
STANDARD-DIRECT-SLOT-DEFINITION, STANDARD-EFFECTIVE-SLOT-DEFINITION,
STRUCTURE-DIRECT-SLOT-DEFINITION, STRUCTURE-EFFECTIVE-SLOT-DEFINITION,
STRUCTURE-SLOT-DEFINITION.  These are not being proposed for standardization
right now.


NON-ANSI-STANDARD SYMBOLS EXPORTED BY THE CLOS PACKAGE, ONLY IN
COMMON LISP IMPLEMENTATIONS THAT HAVE LOCATIVES:

  SLOT-DEFINITION-LOCATORS                   CLOS generic function
  STANDARD-LOCATOR-METHOD                    class name

Notes:

These names are only meaningful in implementations that have the "locatives"
extension, and would not exist in other implementations.  They do not exist in
Symbolics Cloe, nor in Lucid.

Where a function is listed as "LOCFable", that attribute only applies in
implementations that have the "locatives" extension.



ANSI-STANDARD SYMBOLS EXPORTED BY THE CLOS PACKAGE:

While we're at it, I might as well include this list of the symbols that
Symbolics thinks are defined by the CLOS standard.  These are all the symbols
with pages in chapter 2 of 88-002R, plus other symbols that are mentioned in
88-002R with the apparent intention of being part of the standard, plus
several symbols added by later X3J13 actions.

Note that neither Symbolics or Lucid has implemented GENERIC-FLET,
GENERIC-FUNCTION as a special form, GENERIC-LABELS, and WITH-ADDED-METHODS in
their current implementations.  Lucid also has not yet implemented
DEFINE-METHOD-COMBINATION.  The other missing global definitions are because
the standard specifies only a local definition for those symbols.  I think a
careful reading will also show that the implementation from which this table
was generated has not yet implemented a couple of specified condition types.

Lucid exports all of the symbols listed here except for MAKE-LOAD-FORM and
MAKE-LOAD-FORM-SAVING-SLOTS, which are not implemented yet.  (A few others
are only exported by a last-minute patch to the Lucid 4.0.0 Beta-1 version.)

  ADD-METHOD                          CLOS generic function
  ALLOCATE-INSTANCE                   CLOS generic function
  BUILT-IN-CLASS                      class name
  CALL-METHOD                         ***No global definition found*** 
  CALL-NEXT-METHOD                    ***No global definition found*** 
  CHANGE-CLASS                        CLOS generic function
  CLASS                               class name
  CLASS-NAME                          CLOS generic function, SETFable
  CLASS-OF                            function
  COMPUTE-APPLICABLE-METHODS          CLOS generic function
  DEFCLASS                            macro
  DEFGENERIC                          macro
  DEFINE-METHOD-COMBINATION           macro
  DEFMETHOD                           macro
  DESCRIBE-OBJECT                     CLOS generic function
  DOCUMENTATION                       CLOS generic function, SETFable
  ENSURE-GENERIC-FUNCTION             function
  FIND-CLASS                          function, SETFable
  FIND-METHOD                         CLOS generic function
  FUNCTION-KEYWORDS                   CLOS generic function
  GENERIC-FLET                        ***No global definition found*** 
  GENERIC-FUNCTION                    class name
  GENERIC-LABELS                      ***No global definition found*** 
  INITIALIZE-INSTANCE                 CLOS generic function
  INVALID-METHOD-ERROR                function
  MAKE-INSTANCE                       CLOS generic function
  MAKE-INSTANCES-OBSOLETE             CLOS generic function
  MAKE-LOAD-FORM                      CLOS generic function
  MAKE-LOAD-FORM-SAVING-SLOTS         function
  MAKE-METHOD                         ***No global definition found*** 
  METHOD                              class name
  METHOD-COMBINATION                  class name, DOCUMENTATION type
  METHOD-COMBINATION-ERROR            function
  METHOD-QUALIFIERS                   CLOS generic function
  NEXT-METHOD-P                       ***No global definition found*** 
  NO-APPLICABLE-METHOD                CLOS generic function
  NO-NEXT-METHOD                      CLOS generic function
  PRINT-OBJECT                        CLOS generic function
  REINITIALIZE-INSTANCE               CLOS generic function
  REMOVE-METHOD                       CLOS generic function
  SETF                                macro, DOCUMENTATION type
  SHARED-INITIALIZE                   CLOS generic function
  SLOT-BOUNDP                         function
  SLOT-EXISTS-P                       function
  SLOT-MAKUNBOUND                     function
  SLOT-MISSING                        CLOS generic function
  SLOT-UNBOUND                        CLOS generic function
  SLOT-VALUE                          function, SETFable, LOCFable
  STANDARD                            CLOS method-combination
  STANDARD-CLASS                      class name
  STANDARD-GENERIC-FUNCTION           class name
  STANDARD-METHOD                     class name
  STANDARD-OBJECT                     class name
  STRUCTURE-CLASS                     class name
  STRUCTURE-OBJECT                    class name
  SYMBOL-MACROLET                     special form
  UPDATE-INSTANCE-FOR-DIFFERENT-CLASS CLOS generic function
  UPDATE-INSTANCE-FOR-REDEFINED-CLASS CLOS generic function
  WITH-ACCESSORS                      macro
  WITH-ADDED-METHODS                  ***No global definition found*** 
  WITH-SLOTS                          macro

Notes:

ALLOCATE-INSTANCE did not get its own page in 88-002R, but (some of) the
authors of that document say that was simply a mistake.  At this point there
should probably be an X3J13 cleanup to clarify that ALLOCATE-INSTANCE is part
of the language.  Note that LOAD-OBJECTS:MAKE-LOAD-FORM assumes the existence
of ALLOCATE-INSTANCE and that user-written MAKE-LOAD-FORM methods that return
two values will typically use ALLOCATE-INSTANCE in the first value.  The
symbol ALLOCATE-INSTANCE is not exported from the CLOS package by Genera 8.0,
but it is exported by Lucid.  The lack of export in Genera is just a bug.
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