Property list key names

Property list key names

[Lennart Borgman (gmail)]

I guess there is something like this function in Emacs:

(defun property-list-keys (plist)
   "Return list of key names in property list PLIST."
   (let ((keys)
         (plist (copy-list plist)))
     (while plist
       (setq keys (cons (car plist) keys))
       (setq plist (cddr plist)))
     keys))

What is the name of it?

Re: Property list key names

[Juanma Barranquero]

On Sat, Aug 9, 2008 at 15:56, Lennart Borgman (gmail)
<lennart.borgman@gmail.com> wrote:

> I guess there is something like this function in Emacs:

I don't think there's one...

> (defun property-list-keys (plist)
>  "Return list of key names in property list PLIST."
>  (let ((keys)
>        (plist (copy-list plist)))

Why do you copy plist?

>    (while plist
>      (setq keys (cons (car plist) keys))
>      (setq plist (cddr plist)))
>    keys))

> What is the name of it?

It's easy enough to implement, and not much needed (apparently).

If you're using CL, you can get fancy

(defun  property-list-keys (plist)
  (let ((c 0))
    (remove-if #'(lambda (ignore) (zerop (mod (incf c) 2))) plist)))

(not that it is better or clearer than your version, of course ;-)

             Juanma

Re: Property list key names

[Lennart Borgman (gmail)]

Juanma Barranquero wrote:
> On Sat, Aug 9, 2008 at 15:56, Lennart Borgman (gmail)
> <lennart.borgman@gmail.com> wrote:
> 
>> I guess there is something like this function in Emacs:
> 
> I don't think there's one...
> 
>> (defun property-list-keys (plist)
>>  "Return list of key names in property list PLIST."
>>  (let ((keys)
>>        (plist (copy-list plist)))
> 
> Why do you copy plist?

Just a mistake.

>>    (while plist
>>      (setq keys (cons (car plist) keys))
>>      (setq plist (cddr plist)))
>>    keys))
> 
>> What is the name of it?
> 
> It's easy enough to implement, and not much needed (apparently).

Ok, thanks.

> If you're using CL, you can get fancy
> 
> (defun  property-list-keys (plist)
>   (let ((c 0))
>     (remove-if #'(lambda (ignore) (zerop (mod (incf c) 2))) plist)))
> 
> (not that it is better or clearer than your version, of course ;-)

But I learned something ;-)

>              Juanma
> 

Re: Property list key names

[Juanma Barranquero]

On Sat, Aug 9, 2008 at 17:02, Lennart Borgman (gmail)
<lennart.borgman@gmail.com> wrote:

> But I learned something ;-)

Yes. That I am an idiot...

(defun  property-list-keys (plist)
 (let ((c 0))
   (remove-if #'(lambda (ignore) (evenp (incf c))) plist)))

Much simpler.

BTW, the only "advantage" of my version is that the keys are returned in order.

             Juanma

Re: Property list key names

[Lennart Borgman (gmail)]

Juanma Barranquero wrote:
> On Sat, Aug 9, 2008 at 17:02, Lennart Borgman (gmail)
> <lennart.borgman@gmail.com> wrote:
> 
>> But I learned something ;-)
> 
> Yes. That I am an idiot...

Oh, sorry, I missed that ;-)

> (defun  property-list-keys (plist)
>  (let ((c 0))
>    (remove-if #'(lambda (ignore) (evenp (incf c))) plist)))
> 
> Much simpler.
> 
> BTW, the only "advantage" of my version is that the keys are returned in order.

What I am trying to do is finding different CL symbol definitions. I do 
not know CL at all and it is quite frustrating trying to find the 
definition sources. (Though I am beginning to understand defstruct etc now.)

Is there already some library for that?

Re: Property list key names

[Juanma Barranquero]

On Sat, Aug 9, 2008 at 17:11, Lennart Borgman (gmail)
<lennart.borgman@gmail.com> wrote:

> What I am trying to do is finding different CL symbol definitions. I do not
> know CL at all and it is quite frustrating trying to find the definition
> sources. (Though I am beginning to understand defstruct etc now.)

I do not understand.

   Juanma

Re: Property list key names

[Lennart Borgman (gmail)]

Juanma Barranquero wrote:
> On Sat, Aug 9, 2008 at 17:11, Lennart Borgman (gmail)
> <lennart.borgman@gmail.com> wrote:
> 
>> What I am trying to do is finding different CL symbol definitions. I do not
>> know CL at all and it is quite frustrating trying to find the definition
>> sources. (Though I am beginning to understand defstruct etc now.)
> 
> I do not understand.

If there for example is something like this

  (defstruct ert-stats
    (selector (assert nil)))

then a defstruct selector function `ert-stats-selector' is defined. It 
would be nice to go to that function directly from the link in 
`describe-function', but currently the position in the file is not found.

And there is no information at all provided by describe-function that it 
is made by defstruct. Wouldn't it be nice if the CL library added that 
information? I am not very fond of that CL black box game.

Re: Property list key names

[Johan Bockgård]

"Lennart Borgman (gmail)" <lennart.borgman@gmail.com> writes:

> If there for example is something like this
>
>  (defstruct ert-stats
>    (selector (assert nil)))
>
> then a defstruct selector function `ert-stats-selector' is defined. It
> would be nice to go to that function directly from the link in
> describe-function', but currently the position in the file is not
> found.

Indeed, defstruct should put a `definition-name' property on the names
it constructs. Like

(put 'ert-stats-selector 'definition-name 'ert-stats)

-- 
Johan Bockgård

Re: Property list key names

[Lennart Borgman (gmail)]

Johan Bockgård wrote:
> "Lennart Borgman (gmail)" <lennart.borgman@gmail.com> writes:
> 
>> If there for example is something like this
>>
>>  (defstruct ert-stats
>>    (selector (assert nil)))
>>
>> then a defstruct selector function `ert-stats-selector' is defined. It
>> would be nice to go to that function directly from the link in
>> describe-function', but currently the position in the file is not
>> found.
> 
> Indeed, defstruct should put a `definition-name' property on the names
> it constructs. Like
> 
> (put 'ert-stats-selector 'definition-name 'ert-stats)

Yes, something like that. Is 'definition-name special in some way or 
could/should it be something else?

Beside that `ert-stats' does not get any information about where it is 
defined. Is there any reason not to add that information, either to 
load-history (preffered) or to the symbol itself?

Re: Property list key names

[Lennart Borgman (gmail)]

Lennart Borgman (gmail) wrote:
> Beside that `ert-stats' does not get any information about where it is 
> defined. Is there any reason not to add that information, either to 
> load-history (preffered) or to the symbol itself?


And should not `defmacro' be responsible for this?

Re: Property list key names

[Johan Bockgård]

"Lennart Borgman (gmail)" <lennart.borgman@gmail.com> writes:

> Johan Bockgård wrote:
>> "Lennart Borgman (gmail)" <lennart.borgman@gmail.com> writes:
>>
>>> If there for example is something like this
>>>
>>>  (defstruct ert-stats
>>>    (selector (assert nil)))
>>>
>>> then a defstruct selector function `ert-stats-selector' is defined. It
>>> would be nice to go to that function directly from the link in
>>> describe-function', but currently the position in the file is not
>>> found.
>>
>> Indeed, defstruct should put a `definition-name' property on the names
>> it constructs. Like
>>
>> (put 'ert-stats-selector 'definition-name 'ert-stats)
>
> Yes, something like that. Is 'definition-name special in some way or
> could/should it be something else?

Try C-h f again after adding the property above.

-- 
Johan Bockgård

Re: Property list key names

[Lennart Borgman (gmail)]

Johan Bockgård wrote:
> "Lennart Borgman (gmail)" <lennart.borgman@gmail.com> writes:
> 
>> Johan Bockgård wrote:
>>> "Lennart Borgman (gmail)" <lennart.borgman@gmail.com> writes:
>>>
>>>> If there for example is something like this
>>>>
>>>>  (defstruct ert-stats
>>>>    (selector (assert nil)))
>>>>
>>>> then a defstruct selector function `ert-stats-selector' is defined. It
>>>> would be nice to go to that function directly from the link in
>>>> describe-function', but currently the position in the file is not
>>>> found.
>>> Indeed, defstruct should put a `definition-name' property on the names
>>> it constructs. Like
>>>
>>> (put 'ert-stats-selector 'definition-name 'ert-stats)
>> Yes, something like that. Is 'definition-name special in some way or
>> could/should it be something else?
> 
> Try C-h f again after adding the property above.

Hey, that is the black box game again ... ;-)

Yes, you are right, but I do not understand how it works. I guess C-h f 
searches the buffer for the "definition-name".

So this looks like more or less a bug.

I tried to look at defstruct to see where to add 'definition-name. There 
seems to be 4 uses of `defun' and `defsubst*'. Should not all this 4 be 
adding 'definition-name?

Re: Property list key names

[Lennart Borgman (gmail)]

Lennart Borgman (gmail) wrote:
> Johan Bockgård wrote:
>> "Lennart Borgman (gmail)" <lennart.borgman@gmail.com> writes:
>>
>>> Johan Bockgård wrote:
>>>> "Lennart Borgman (gmail)" <lennart.borgman@gmail.com> writes:
>>>>
>>>>> If there for example is something like this
>>>>>
>>>>>  (defstruct ert-stats
>>>>>    (selector (assert nil)))
>>>>>
>>>>> then a defstruct selector function `ert-stats-selector' is defined. It
>>>>> would be nice to go to that function directly from the link in
>>>>> describe-function', but currently the position in the file is not
>>>>> found.
>>>> Indeed, defstruct should put a `definition-name' property on the names
>>>> it constructs. Like
>>>>
>>>> (put 'ert-stats-selector 'definition-name 'ert-stats)
>>> Yes, something like that. Is 'definition-name special in some way or
>>> could/should it be something else?
>>
>> Try C-h f again after adding the property above.
> 
> Hey, that is the black box game again ... ;-)
> 
> Yes, you are right, but I do not understand how it works. I guess C-h f 
> searches the buffer for the "definition-name".
> 
> So this looks like more or less a bug.
> 
> I tried to look at defstruct to see where to add 'definition-name. There 
> seems to be 4 uses of `defun' and `defsubst*'. Should not all this 4 be 
> adding 'definition-name?


Here is a patch for that. Should be wrapped a bit, but it is easier 
seeing what I have done if it is like this. Should the (put ... 
'definition-name ...) be before or after the defmacro* and defun in the 
code?

Re: Property list key names

[Lennart Borgman (gmail)]

[-- Attachment #1: Type: text/plain, Size: 1640 bytes --]

Lennart Borgman (gmail) wrote:
> Lennart Borgman (gmail) wrote:
>> Johan Bockgård wrote:
>>> "Lennart Borgman (gmail)" <lennart.borgman@gmail.com> writes:
>>>
>>>> Johan Bockgård wrote:
>>>>> "Lennart Borgman (gmail)" <lennart.borgman@gmail.com> writes:
>>>>>
>>>>>> If there for example is something like this
>>>>>>
>>>>>>  (defstruct ert-stats
>>>>>>    (selector (assert nil)))
>>>>>>
>>>>>> then a defstruct selector function `ert-stats-selector' is 
>>>>>> defined. It
>>>>>> would be nice to go to that function directly from the link in
>>>>>> describe-function', but currently the position in the file is not
>>>>>> found.
>>>>> Indeed, defstruct should put a `definition-name' property on the names
>>>>> it constructs. Like
>>>>>
>>>>> (put 'ert-stats-selector 'definition-name 'ert-stats)
>>>> Yes, something like that. Is 'definition-name special in some way or
>>>> could/should it be something else?
>>>
>>> Try C-h f again after adding the property above.
>>
>> Hey, that is the black box game again ... ;-)
>>
>> Yes, you are right, but I do not understand how it works. I guess C-h 
>> f searches the buffer for the "definition-name".
>>
>> So this looks like more or less a bug.
>>
>> I tried to look at defstruct to see where to add 'definition-name. 
>> There seems to be 4 uses of `defun' and `defsubst*'. Should not all 
>> this 4 be adding 'definition-name?
> 
> 
> Here is a patch for that. Should be wrapped a bit, but it is easier 
> seeing what I have done if it is like this. Should the (put ... 
> 'definition-name ...) be before or after the defmacro* and defun in the 
> code?


Sorry, attached the patch.

[-- Attachment #2: cl-macs-definition-name.diff --]
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Index: cl-macs.el
===================================================================
RCS file: /sources/emacs/emacs/lisp/emacs-lisp/cl-macs.el,v
retrieving revision 1.76
diff -u -r1.76 cl-macs.el
--- cl-macs.el	16 Jul 2008 02:50:00 -0000	1.76
+++ cl-macs.el	9 Aug 2008 18:44:42 -0000
@@ -2328,6 +2328,7 @@
 			 (list (if (eq type 'vector) (list 'aref 'cl-x pos)
 				 (if (= pos 0) '(car cl-x)
 				   (list 'nth pos 'cl-x)))))) forms)
+              (push (list 'put (list 'quote accessor) (list 'quote 'definition-name) (list 'quote struct)) forms)
 	      (push (cons accessor t) side-eff)
 	      (push (list 'define-setf-method accessor '(cl-x)
 			     (if (cadr (memq :read-only (cddr desc)))
@@ -2355,9 +2356,11 @@
 			       (if (eq (car pred-form) 'and)
 				   (append pred-form '(t))
 				 (list 'and pred-form t))) forms)
+                (push (list 'put (list 'quote predicate) (list 'quote 'definition-name) (list 'quote struct)) forms)
 		(push (cons predicate 'error-free) side-eff)))
     (and copier
 	 (progn (push (list 'defun copier '(x) '(copy-sequence x)) forms)
+                (push (list 'put (list 'quote copier) (list 'quote 'definition-name) (list 'quote struct)) forms)
 		(push (cons copier t) side-eff)))
     (if constructor
 	(push (list constructor
@@ -2372,6 +2375,7 @@
 	(push (list 'defsubst* name
 		       (list* '&cl-defs (list 'quote (cons nil descs)) args)
 		       (cons type make)) forms)
+        (push (list 'put (list 'quote name) (list 'quote 'definition-name) (list 'quote struct)) forms)
 	(if (cl-safe-expr-p (cons 'progn (mapcar 'second descs)))
 	    (push (cons name t) side-eff))))
     (if print-auto (nconc print-func (list '(princ ")" cl-s) t)))

Re: Property list key names

[Johan Bockgård]

"Juanma Barranquero" <lekktu@gmail.com> writes:

> If you're using CL, you can get fancy

(loop for x in plist by 'cddr
      collect x)

Re: Property list key names

[Juanma Barranquero]

On Sat, Aug 9, 2008 at 17:08, Johan Bockgård
<bojohan+news@dd.chalmers.se> wrote:

> (loop for x in plist by 'cddr
>      collect x)

Yes, of course. I tend not to use `loop' because of code formatting
issues, but certainly you can do everything with it :-)

 Juanma