* bug#25294: 26.0.50; Allow more catch-all values for cl-defmethod's &context plus major-mode specializer
@ 2016-12-29 19:13 Eric Abrahamsen
2016-12-30 4:35 ` npostavs
2017-12-12 1:39 ` Noam Postavsky
0 siblings, 2 replies; 10+ messages in thread
From: Eric Abrahamsen @ 2016-12-29 19:13 UTC (permalink / raw)
To: 25294
When defining a method using cl-defmethod with the &context and
major-mode specializer, there should be more acceptable options for
catch-all or fall-through methods. Ie, we want to create a method that
fires regardless of the major mode. These signatures don't work, but
should:
(cl-defmethod example-method ((&context (major-mode fundamental-mode))))
(cl-defmethod example-method ((&context (major-mode nil)))
(cl-defmethod example-method ((&context (major-mode t))))
Right now the only thing that works is:
(cl-defmethod example-method ())
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^ permalink raw reply [flat|nested] 10+ messages in thread
* bug#25294: 26.0.50; Allow more catch-all values for cl-defmethod's &context plus major-mode specializer
2016-12-29 19:13 bug#25294: 26.0.50; Allow more catch-all values for cl-defmethod's &context plus major-mode specializer Eric Abrahamsen
@ 2016-12-30 4:35 ` npostavs
2017-12-11 23:57 ` Eric Abrahamsen
2017-12-12 1:39 ` Noam Postavsky
1 sibling, 1 reply; 10+ messages in thread
From: npostavs @ 2016-12-30 4:35 UTC (permalink / raw)
To: Eric Abrahamsen; +Cc: 25294
Eric Abrahamsen <eric@ericabrahamsen.net> writes:
> When defining a method using cl-defmethod with the &context and
> major-mode specializer,
Is this about the undocumented specializer mentioned in cl-generic.el?
;;; Dispatch on major mode.
;; Two parts:
;; - first define a specializer (derived-mode <mode>) to match symbols
;; representing major modes, while obeying the major mode hierarchy.
;; - then define a context-rewriter so you can write
;; "&context (major-mode c-mode)" rather than
;; "&context (major-mode (derived-mode c-mode))".
> there should be more acceptable options for
> catch-all or fall-through methods. Ie, we want to create a method that
> fires regardless of the major mode.
If you want to ignore the major mode, why do you want to use the
major-mode specializer?
> These signatures don't work, but
> should:
>
> (cl-defmethod example-method ((&context (major-mode fundamental-mode))))
>
Should that be
(cl-defmethod example-method (&context (major-mode fundamental-mode)))
The reason this doesn't work is because fundamental isn't actually the
parent mode of text-mode or prog-mode, i.e., (get 'text-mode
'derived-mode-parent) => nil.
> (cl-defmethod example-method ((&context (major-mode nil)))
>
> (cl-defmethod example-method ((&context (major-mode t))))
>
> Right now the only thing that works is:
>
> (cl-defmethod example-method ())
^ permalink raw reply [flat|nested] 10+ messages in thread
* bug#25294: 26.0.50; Allow more catch-all values for cl-defmethod's &context plus major-mode specializer
2016-12-30 4:35 ` npostavs
@ 2017-12-11 23:57 ` Eric Abrahamsen
2017-12-12 0:08 ` Noam Postavsky
0 siblings, 1 reply; 10+ messages in thread
From: Eric Abrahamsen @ 2017-12-11 23:57 UTC (permalink / raw)
To: npostavs; +Cc: 25294
Ahem, I only just noticed (a year later) that there was a response to
this when I searched for bug reports I'd opened -- sorry about that.
> Is this about the undocumented specializer mentioned in cl-generic.el?
>
> ;;; Dispatch on major mode.
>
> ;; Two parts:
> ;; - first define a specializer (derived-mode <mode>) to match symbols
> ;; representing major modes, while obeying the major mode hierarchy.
> ;; - then define a context-rewriter so you can write
> ;; "&context (major-mode c-mode)" rather than
> ;; "&context (major-mode (derived-mode c-mode))".
Yes, that's it.
>> there should be more acceptable options for
>> catch-all or fall-through methods. Ie, we want to create a method that
>> fires regardless of the major mode.
>
> If you want to ignore the major mode, why do you want to use the
> major-mode specializer?
It's the equivalent of the "t" branch in a `cond' statement. You write
methods to handle specific major modes, and write another method to
handle the catch-all case of "all other modes".
>> These signatures don't work, but
>> should:
>>
>> (cl-defmethod example-method ((&context (major-mode fundamental-mode))))
>>
>
> Should that be
>
> (cl-defmethod example-method (&context (major-mode fundamental-mode)))
>
> The reason this doesn't work is because fundamental isn't actually the
> parent mode of text-mode or prog-mode, i.e., (get 'text-mode
> 'derived-mode-parent) => nil.
Right -- I still think either t or nil should do it.
^ permalink raw reply [flat|nested] 10+ messages in thread
* bug#25294: 26.0.50; Allow more catch-all values for cl-defmethod's &context plus major-mode specializer
2017-12-11 23:57 ` Eric Abrahamsen
@ 2017-12-12 0:08 ` Noam Postavsky
0 siblings, 0 replies; 10+ messages in thread
From: Noam Postavsky @ 2017-12-12 0:08 UTC (permalink / raw)
To: Eric Abrahamsen; +Cc: 25294
Eric Abrahamsen <eric@ericabrahamsen.net> writes:
> Ahem, I only just noticed (a year later) that there was a response to
> this when I searched for bug reports I'd opened -- sorry about that.
It's had lots of time to rest then :)
>> If you want to ignore the major mode, why do you want to use the
>> major-mode specializer?
>
> It's the equivalent of the "t" branch in a `cond' statement. You write
> methods to handle specific major modes, and write another method to
> handle the catch-all case of "all other modes".
Still not really convinced by this, what's wrong with the last way you
put in your OP:
(cl-defmethod example-method ())
^ permalink raw reply [flat|nested] 10+ messages in thread
* bug#25294: 26.0.50; Allow more catch-all values for cl-defmethod's &context plus major-mode specializer
2016-12-29 19:13 bug#25294: 26.0.50; Allow more catch-all values for cl-defmethod's &context plus major-mode specializer Eric Abrahamsen
2016-12-30 4:35 ` npostavs
@ 2017-12-12 1:39 ` Noam Postavsky
2017-12-12 1:43 ` Noam Postavsky
2017-12-12 5:42 ` Eric Abrahamsen
1 sibling, 2 replies; 10+ messages in thread
From: Noam Postavsky @ 2017-12-12 1:39 UTC (permalink / raw)
To: 25294; +Cc: Eric Abrahamsen
[-- Attachment #1: Type: text/plain, Size: 22 bytes --]
[forwarding to list]
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From: Eric Abrahamsen <eric@ericabrahamsen.net>
To: Noam Postavsky <npostavs@users.sourceforge.net>
Subject: Re: bug#25294: 26.0.50; Allow more catch-all values for cl-defmethod's &context plus major-mode specializer
Date: Mon, 11 Dec 2017 16:49:14 -0800
Message-ID: <87y3m8rcs5.fsf@ericabrahamsen.net>
On 12/11/17 19:08 PM, Noam Postavsky wrote:
> Eric Abrahamsen <eric@ericabrahamsen.net> writes:
>
>> Ahem, I only just noticed (a year later) that there was a response to
>> this when I searched for bug reports I'd opened -- sorry about that.
>
> It's had lots of time to rest then :)
>
>>> If you want to ignore the major mode, why do you want to use the
>>> major-mode specializer?
>>
>> It's the equivalent of the "t" branch in a `cond' statement. You write
>> methods to handle specific major modes, and write another method to
>> handle the catch-all case of "all other modes".
>
> Still not really convinced by this, what's wrong with the last way you
> put in your OP:
>
> (cl-defmethod example-method ())
A year later, older and wiser, I agree that maybe all that's needed is
more documentation. I just noticed that, at some point in the interim,
the documentation for generic functions has been greatly expanded, which
is nice!
I'd like to add the following to the docs:
1. The &context thing has to come after the required arguments, but
before any &optional or &rest things.
2. You can have an arbitrary number of forms following &context.
3. The &context arguments don't have to match the declared arguments in
`cl-defgeneric'.
4. Ergo they can be left off altogether without needing to be
specifically declared as nil or what have you, ie, my original bug
report isn't really a bug.
If this looks okay, I'll have at the docs.
Eric
^ permalink raw reply [flat|nested] 10+ messages in thread
* bug#25294: 26.0.50; Allow more catch-all values for cl-defmethod's &context plus major-mode specializer
2017-12-12 1:39 ` Noam Postavsky
@ 2017-12-12 1:43 ` Noam Postavsky
2017-12-12 5:42 ` Eric Abrahamsen
1 sibling, 0 replies; 10+ messages in thread
From: Noam Postavsky @ 2017-12-12 1:43 UTC (permalink / raw)
To: 25294; +Cc: Eric Abrahamsen
> From: Eric Abrahamsen <eric@ericabrahamsen.net>
> Subject: Re: bug#25294: 26.0.50; Allow more catch-all values for cl-defmethod's &context plus major-mode specializer
> To: Noam Postavsky <npostavs@users.sourceforge.net>
> Date: Mon, 11 Dec 2017 16:49:14 -0800 (51 minutes, 9 seconds ago)
>
>> Still not really convinced by this, what's wrong with the last way you
>> put in your OP:
>>
>> (cl-defmethod example-method ())
>
> A year later, older and wiser, I agree that maybe all that's needed is
> more documentation. I just noticed that, at some point in the interim,
> the documentation for generic functions has been greatly expanded, which
> is nice!
>
> I'd like to add the following to the docs:
>
> 1. The &context thing has to come after the required arguments, but
> before any &optional or &rest things.
> 2. You can have an arbitrary number of forms following &context.
> 3. The &context arguments don't have to match the declared arguments in
> `cl-defgeneric'.
> 4. Ergo they can be left off altogether without needing to be
> specifically declared as nil or what have you, ie, my original bug
> report isn't really a bug.
>
> If this looks okay, I'll have at the docs.
Sounds good to me.
^ permalink raw reply [flat|nested] 10+ messages in thread
* bug#25294: 26.0.50; Allow more catch-all values for cl-defmethod's &context plus major-mode specializer
2017-12-12 1:39 ` Noam Postavsky
2017-12-12 1:43 ` Noam Postavsky
@ 2017-12-12 5:42 ` Eric Abrahamsen
2017-12-12 23:58 ` Noam Postavsky
1 sibling, 1 reply; 10+ messages in thread
From: Eric Abrahamsen @ 2017-12-12 5:42 UTC (permalink / raw)
To: Noam Postavsky; +Cc: 25294
[-- Attachment #1: Type: text/plain, Size: 933 bytes --]
Noam Postavsky <npostavs@users.sourceforge.net> writes:
> [forwarding to list]
Whoops, sorry.
[...]
>> A year later, older and wiser, I agree that maybe all that's needed is
>> more documentation. I just noticed that, at some point in the interim,
>> the documentation for generic functions has been greatly expanded, which
>> is nice!
>>
>> I'd like to add the following to the docs:
>>
>> 1. The &context thing has to come after the required arguments, but
>> before any &optional or &rest things.
>> 2. You can have an arbitrary number of forms following &context.
>> 3. The &context arguments don't have to match the declared arguments in
>> `cl-defgeneric'.
>> 4. Ergo they can be left off altogether without needing to be
>> specifically declared as nil or what have you, ie, my original bug
>> report isn't really a bug.
>>
>> If this looks okay, I'll have at the docs.
> Sounds good to me.
Here's my diff.
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: context-spec-docs.diff --]
[-- Type: text/x-patch, Size: 1910 bytes --]
diff --git a/doc/lispref/functions.texi b/doc/lispref/functions.texi
index 466a12f7a4..6b98a3d639 100644
--- a/doc/lispref/functions.texi
+++ b/doc/lispref/functions.texi
@@ -1252,15 +1252,21 @@ Generic Functions
Extensions for GNU Emacs Lisp}), or of one of its parent classes.
@end table
-Alternatively, the argument specializer can be of the form
-@code{&context (@var{expr} @var{spec})}, in which case the value of
-@var{expr} must be compatible with the specializer provided by
-@var{spec}; @var{spec} can be any of the forms described above. In
-other words, this form of specializer uses the value of @var{expr}
-instead of arguments for the decision whether the method is
-applicable. For example, @code{&context (overwrite-mode (eql t))}
-will make the method compatible only when @code{overwrite-mode} is
-turned on.
+Generic functions provide a new argument-list keyword,
+@code{&context}, which can be used to introduce extra specializers
+that test the general environment in which the method is run. This
+keyword should appear after the list of required arguments, but before
+any @code{&rest} or @code{&optional} keywords. The @code{&context}
+specializers look much like regular argument
+specializers---(@var{expr} @var{spec})---except that @var{expr} is an
+expression to be evaluated in the current context, and the @var{spec}
+is a value to compare against. For example, @code{&context
+(overwrite-mode (eql t))} will make the method applicable only when
+@code{overwrite-mode} is turned on. The @code{&context} keyword can
+be followed by any number of context specializers. Because the
+context specializers are not part of the generic function's required
+argument signature, they may be omitted in methods that don't require
+them.
The type specializer, @code{(@var{arg} @var{type})}, can specify one
of the @dfn{system types} in the following list. When a parent type
^ permalink raw reply related [flat|nested] 10+ messages in thread
* bug#25294: 26.0.50; Allow more catch-all values for cl-defmethod's &context plus major-mode specializer
2017-12-12 5:42 ` Eric Abrahamsen
@ 2017-12-12 23:58 ` Noam Postavsky
2017-12-14 0:06 ` Eric Abrahamsen
2017-12-14 21:01 ` Eric Abrahamsen
0 siblings, 2 replies; 10+ messages in thread
From: Noam Postavsky @ 2017-12-12 23:58 UTC (permalink / raw)
To: Eric Abrahamsen; +Cc: 25294
Eric Abrahamsen <eric@ericabrahamsen.net> writes:
> +Generic functions provide a new argument-list keyword,
The way you phrased this might lead me to think that the &context
keyword should go in the cl-defgeneric form (maybe it's not so bad when
seeing in context under cl-defmethod, in patch form it's a bit
disconnected).
> +@code{&context}, which can be used to introduce extra specializers
> +that test the general environment in which the method is run. This
> +keyword should appear after the list of required arguments, but before
> +any @code{&rest} or @code{&optional} keywords.
I wonder if it would be clearer to add this to the @defmac header?
@defmac cl-defmethod name [qualifier] arguments [&context (expr spec)@dots{}] &rest [docstring] body
Hmm, maybe that ends up being too long.
> The @code{&context}
> +specializers look much like regular argument
> +specializers---(@var{expr} @var{spec})---except that @var{expr} is an
> +expression to be evaluated in the current context, and the @var{spec}
> +is a value to compare against. For example, @code{&context
> +(overwrite-mode (eql t))} will make the method applicable only when
> +@code{overwrite-mode} is turned on. The @code{&context} keyword can
> +be followed by any number of context specializers. Because the
> +context specializers are not part of the generic function's required
> +argument signature, they may be omitted in methods that don't require
> +them.
Otherwise looks fine.
^ permalink raw reply [flat|nested] 10+ messages in thread
* bug#25294: 26.0.50; Allow more catch-all values for cl-defmethod's &context plus major-mode specializer
2017-12-12 23:58 ` Noam Postavsky
@ 2017-12-14 0:06 ` Eric Abrahamsen
2017-12-14 21:01 ` Eric Abrahamsen
1 sibling, 0 replies; 10+ messages in thread
From: Eric Abrahamsen @ 2017-12-14 0:06 UTC (permalink / raw)
To: Noam Postavsky; +Cc: 25294
Noam Postavsky <npostavs@users.sourceforge.net> writes:
> Eric Abrahamsen <eric@ericabrahamsen.net> writes:
>
>> +Generic functions provide a new argument-list keyword,
>
> The way you phrased this might lead me to think that the &context
> keyword should go in the cl-defgeneric form (maybe it's not so bad when
> seeing in context under cl-defmethod, in patch form it's a bit
> disconnected).
Maybe so, yes. I'll look at it in context and see if I can't make that a
little clearer.
>> +@code{&context}, which can be used to introduce extra specializers
>> +that test the general environment in which the method is run. This
>> +keyword should appear after the list of required arguments, but before
>> +any @code{&rest} or @code{&optional} keywords.
>
> I wonder if it would be clearer to add this to the @defmac header?
>
> @defmac cl-defmethod name [qualifier] arguments [&context (expr spec)@dots{}] &rest [docstring] body
>
> Hmm, maybe that ends up being too long.
I never found those things very helpful, and that does look a little long...
^ permalink raw reply [flat|nested] 10+ messages in thread
* bug#25294: 26.0.50; Allow more catch-all values for cl-defmethod's &context plus major-mode specializer
2017-12-12 23:58 ` Noam Postavsky
2017-12-14 0:06 ` Eric Abrahamsen
@ 2017-12-14 21:01 ` Eric Abrahamsen
1 sibling, 0 replies; 10+ messages in thread
From: Eric Abrahamsen @ 2017-12-14 21:01 UTC (permalink / raw)
To: Noam Postavsky; +Cc: 25294
close 25294
quit
On 12/12/17 18:58 PM, Noam Postavsky wrote:
> Eric Abrahamsen <eric@ericabrahamsen.net> writes:
>
>> +Generic functions provide a new argument-list keyword,
>
> The way you phrased this might lead me to think that the &context
> keyword should go in the cl-defgeneric form (maybe it's not so bad when
> seeing in context under cl-defmethod, in patch form it's a bit
> disconnected).
>
>> +@code{&context}, which can be used to introduce extra specializers
>> +that test the general environment in which the method is run. This
>> +keyword should appear after the list of required arguments, but before
>> +any @code{&rest} or @code{&optional} keywords.
>
> I wonder if it would be clearer to add this to the @defmac header?
>
> @defmac cl-defmethod name [qualifier] arguments [&context (expr spec)@dots{}] &rest [docstring] body
>
> Hmm, maybe that ends up being too long.
>
>> The @code{&context}
>> +specializers look much like regular argument
>> +specializers---(@var{expr} @var{spec})---except that @var{expr} is an
>> +expression to be evaluated in the current context, and the @var{spec}
>> +is a value to compare against. For example, @code{&context
>> +(overwrite-mode (eql t))} will make the method applicable only when
>> +@code{overwrite-mode} is turned on. The @code{&context} keyword can
>> +be followed by any number of context specializers. Because the
>> +context specializers are not part of the generic function's required
>> +argument signature, they may be omitted in methods that don't require
>> +them.
>
> Otherwise looks fine.
>
Okay, that's pushed, I ended up adding the bit to the defmac statement
after all, it wraps and shouldn't be too big a deal.
Thanks,
Eric
^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2017-12-14 21:01 UTC | newest]
Thread overview: 10+ messages (download: mbox.gz follow: Atom feed
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2016-12-29 19:13 bug#25294: 26.0.50; Allow more catch-all values for cl-defmethod's &context plus major-mode specializer Eric Abrahamsen
2016-12-30 4:35 ` npostavs
2017-12-11 23:57 ` Eric Abrahamsen
2017-12-12 0:08 ` Noam Postavsky
2017-12-12 1:39 ` Noam Postavsky
2017-12-12 1:43 ` Noam Postavsky
2017-12-12 5:42 ` Eric Abrahamsen
2017-12-12 23:58 ` Noam Postavsky
2017-12-14 0:06 ` Eric Abrahamsen
2017-12-14 21:01 ` Eric Abrahamsen
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