before and after methods

[Didier Verna]

Hi!

Does anyone know why the non-standard built-in method combinations do
not support before and after methods?

Thanks.

[Sam Steingold]

Post by Didier Verna
Does anyone know why the non-standard built-in method combinations do
not support before and after methods?

If you are defining the method combination, you have way more freedom
and flexibility than mere before and after.
Basically, you can do it yourself.

[zbyszek]

Post by Sam Steingold

Post by Didier Verna
Does anyone know why the non-standard built-in method combinations do
not support before and after methods?

If you are defining the method combination, you have way more freedom
and flexibility than mere before and after.
Basically, you can do it yourself.

But Didier is asking about BUILT-IN method combinations. Possibly
it was hard to define reasonable agreed semantics for before an after
methods in the case of something like AND or APPEND (technical troubles
aside).

Regards

ZJ

[Didier Verna]

Post by Sam Steingold
If you are defining the method combination, you have way more freedom
and flexibility than mere before and after. Basically, you can do it
yourself.

But Didier is asking about BUILT-IN method combinations. Possibly it
was hard to define reasonable agreed semantics for before an after
methods in the case of something like AND or APPEND (technical
troubles aside).

Right. I was merely curious. It's pretty obvious to me why you
wouldn't allow CALL-NEXT-METHOD in non-standard built-in combinations,
but I can't figure out why or how before and after methods could be
problematic, so I was wondering...

[Pascal Costanza]

Post by Didier Verna

Post by Sam Steingold
If you are defining the method combination, you have way more freedom
and flexibility than mere before and after. Basically, you can do it
yourself.

But Didier is asking about BUILT-IN method combinations. Possibly it
was hard to define reasonable agreed semantics for before an after
methods in the case of something like AND or APPEND (technical
troubles aside).

Right. I was merely curious. It's pretty obvious to me why you
wouldn't allow CALL-NEXT-METHOD in non-standard built-in combinations,
but I can't figure out why or how before and after methods could be
problematic, so I was wondering...

I’m just guessing, but one reason I can think of is that almost all of the built-in method combinations (except for standard and progn) are applicative. before/after methods don’t have a direct impact on the return value of a generic function call, so their primary purpose is to allow for specifying side effects, which presumably doesn’t make a lot of sense for applicative combinators.

Does that make any sense?

Pascal

--
Pascal Costanza
The views expressed in this email are my own, and not those of my employer.

[Didier Verna]

I’m just guessing, but one reason I can think of is that almost all of
the built-in method combinations (except for standard and progn) are
applicative. before/after methods don’t have a direct impact on the
return value of a generic function call, so their primary purpose is
to allow for specifying side effects, which presumably doesn’t make a
lot of sense for applicative combinators.
Does that make any sense?

Hmmm. Nope :-) Not much to me at least. I have several cases where I
would have liked to be able to perform some kinds of sanity checks
before executing a combination such as AND OR etc.

I can still manage to do it in an around method, but it feels wrong.

[Pascal Costanza]

Post by Didier Verna

Post by Pascal Costanza
I’m just guessing, but one reason I can think of is that almost all of
the built-in method combinations (except for standard and progn) are
applicative. before/after methods don’t have a direct impact on the
return value of a generic function call, so their primary purpose is
to allow for specifying side effects, which presumably doesn’t make a
lot of sense for applicative combinators.
Does that make any sense?

Hmmm. Nope :-)

Darn. :-)

--
Pascal Costanza

[Ken Tilton]

Ah, but the OP specified "built-in" along with "non-standard".

hth

-hk

Post by Sam Steingold

Post by Didier Verna
Does anyone know why the non-standard built-in method combinations do
not support before and after methods?

If you are defining the method combination, you have way more freedom
and flexibility than mere before and after.
Basically, you can do it yourself.
--
Sam Steingold (http://sds.podval.org/) on darwin Ns 10.3.1504
http://steingoldpsychology.com http://www.childpsy.net
https://ffii.org http://camera.org http://think-israel.org
http://no2bds.org
Do not worry about which side your bread is buttered on: you eat BOTH sides.

--
*Ken **Tilton *|Software Engineer
*w:* [phone] *e:* ***@weather.com
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps>

[Steve Haflich]

You're apparently confusing two different meaning of "standard". It's not
the meaning that something is defined in the ANS and therefore built into
the standard ANSI CL language. Rather, it is a standard
method-combination that is not the one known as STANDARD-METHOD-COMBINATION.

Post by Ken Tilton
Ah, but the OP specified "built-in" along with "non-standard".
hth
-hk

Post by Sam Steingold

Post by Didier Verna
Does anyone know why the non-standard built-in method combinations do
not support before and after methods?

If you are defining the method combination, you have way more freedom
and flexibility than mere before and after.
Basically, you can do it yourself.
--
Sam Steingold (http://sds.podval.org/) on darwin Ns 10.3.1504
http://steingoldpsychology.com http://www.childpsy.net
https://ffii.org http://camera.org http://think-israel.org
http://no2bds.org
Do not worry about which side your bread is buttered on: you eat BOTH sides.

--
*Ken **Tilton *|Software Engineer
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps>

[Steve Haflich]

As for the original question, I don't see any reason the various built-in
method combination could not have been defined to support :before and
:after methods. But the way they are defined is consonant with the short
form of define-method-combination, which implies that the several built-in
method combinations would typically be implemented using short form d-m-c.
So the scope of the original question probably should be expanded to
include short form d-m-c.

Post by Steve Haflich
You're apparently confusing two different meaning of "standard". It's not
the meaning that something is defined in the ANS and therefore built into
the standard ANSI CL language. Rather, it is a standard
method-combination that is not the one known as STANDARD-METHOD-COMBINATION.

Post by Ken Tilton
Ah, but the OP specified "built-in" along with "non-standard".
hth
-hk

Post by Sam Steingold

Post by Didier Verna
Does anyone know why the non-standard built-in method combinations do
not support before and after methods?

If you are defining the method combination, you have way more freedom
and flexibility than mere before and after.
Basically, you can do it yourself.
--
Sam Steingold (http://sds.podval.org/) on darwin Ns 10.3.1504
http://steingoldpsychology.com http://www.childpsy.net
https://ffii.org http://camera.org http://think-israel.org
http://no2bds.org
Do not worry about which side your bread is buttered on: you eat BOTH sides.

--
*Ken **Tilton *|Software Engineer
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps> <http://weather.com/apps>
<http://weather.com/apps>

[Didier Verna]

Post by Steve Haflich
As for the original question, I don't see any reason the various
built-in method combination could not have been defined to support
:before and :after methods. But the way they are defined is consonant
with the short form of define-method-combination, which implies that
the several built-in method combinations would typically be
implemented using short form d-m-c. So the scope of the original
question probably should be expanded to include short form d-m-c.

Good point.