widget-create 'menu-choice

widget-create 'menu-choice

[Mortimer Cladwell]

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Hi,

I would like to dynamically populate a dropdown widget from a database.  the 'menu-choice widget looks like

(widget-create 'menu-choice
        :tag "Select Host Species"
        :value "unknown"
                 :notify (lambda (widget &rest ignore)
                           (setq host-species (widget-value widget)))
    '(item "human") 
    '(item "rat") 
    '(item "mouse")) 

Suppose I can generate a list '( "human "rat" "mouse") from the database.  How to create

   '(item "human") 
    '(item "rat") 
    '(item "mouse")

on the fly?  The closest I can come is 

(progn
  (setq var '( "human" "rat" "mouse"))
(mapcar '(lambda  (a)  `'(item ,a))  var)
)

Thanks

Mortimer


      

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Re: widget-create 'menu-choice

[Kevin Rodgers]

Mortimer Cladwell wrote:
> Hi,
>  
> I would like to dynamically populate a dropdown widget from a database.  
> the 'menu-choice widget looks like
>  
> (widget-create 'menu-choice
>         :tag "Select Host Species"
>         :value "unknown"
>                  :notify (lambda (widget &rest ignore)
>                            (setq host-species (widget-value widget)))
>     '(item "human")
>     '(item "rat")
>     '(item "mouse"))
> Suppose I can generate a list '( "human "rat" "mouse") from the 
> database.  How to create
>  
>    '(item "human")
>     '(item "rat")
>     '(item "mouse")
>  
> on the fly?  The closest I can come is
>  
> (progn
>   (setq var '( "human" "rat" "mouse"))
> (mapcar '(lambda  (a)  `'(item ,a))  var)
> )

i.e.

(let ((var '("human" "rat" "mouse")))
   (mapcar (lambda (label) (list 'item label))
	  var))

-- 
Kevin Rodgers
Denver, Colorado, USA

Re:Re: widget-create 'menu-choice

[Mortimer Cladwell]

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Your suggestion evaluates to:

((item "human") (item "rat") (item "mouse"))

which when inserted into a form results in the error:

widget-create: Invalid function: (item "human")

Evaluations that would work are:

'(item "human") '(item "rat") '(item "mouse")
OR 

(quote (item "human"))  (quote (item "rat")) (quote (item "mouse"))

Note that there are no enclosing parenthesis around the list.
Thanks
Mortimer-----------------------------------------------------------------

Mortimer Cladwell wrote: 
Hi,
>I would like to dynamically populate a dropdown widget from a database. the 'menu-choice widget looks like
>(widget-create 'menu-choice
>:tag "Select Host Species"
>:value "unknown"
>:notify (lambda (widget &rest ignore)
>(setq host-species (widget-value widget)))
>'(item "human")
>'(item "rat")
>'(item "mouse"))
>Suppose I can generate a list '( "human "rat" "mouse") from the database. How to create
>'(item "human")
>'(item "rat")
>'(item "mouse")
>on the fly? The closest I can come is
>(progn
>(setq var '( "human" "rat" "mouse"))
>(mapcar '(lambda (a) `'(item ,a)) var)
>) 

i.e.

(let ((var '("human" "rat" "mouse")))
  (mapcar (lambda (label) (list 'item label))
          var))

--
Kevin Rodgers
Denver, Colorado, USA


      

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Re: widget-create 'menu-choice

[Andreas Politz]

Mortimer Cladwell <mbcladwell@yahoo.com> writes:

> Hi,
>  
> I would like to dynamically populate a dropdown widget from a
> database.  the 'menu-choice widget looks like
>  
> (widget-create 'menu-choice
>         :tag "Select Host Species"
>         :value "unknown"
>                  :notify (lambda (widget &rest ignore)
>                            (setq host-species (widget-value
> widget)))
>     '(item "human")
>     '(item "rat")
>     '(item "mouse"))
> Suppose I can generate a list '( "human "rat" "mouse") from the
> database.  How to create
>  
>    '(item "human")
>     '(item "rat")
>     '(item "mouse")
>  
> on the fly?  The closest I can come is
>  
> (progn
>   (setq var '( "human" "rat" "mouse"))
> (mapcar '(lambda  (a)  `'(item ,a))  var)
> )
> Thanks
>  
> Mortimer

`apply' solves this problem.

(apply #'* 1 2 3 '(4 5))

-ap

Re: widget-create 'menu-choice

[Kevin Rodgers]

Mortimer Cladwell wrote:
> Your suggestion evaluates to:
>  
> ((item "human") (item "rat") (item "mouse"))
>  
> which when inserted into a form results in the error:
>  
> widget-create: Invalid function: (item "human")

Ah, I misread the widget-create arguments.  That function's doc string is
practically useless.

> Evaluations that would work are:
>  
> '(item "human") '(item "rat") '(item "mouse")
> OR
> 
> (quote (item "human"))  (quote (item "rat")) (quote (item "mouse"))
 >
> Note that there are no enclosing parenthesis around the list.

As Andreas points out, you need apply:

(defvar species '("human" "rat" "mouse"))

(apply 'widget-create
        'menu-choice
        :tag "Select Host Species"
        :value "unknown"
        :notify (lambda (widget &rest ignore)
		 (setq host-species (widget-value widget)))
        (mapcar (lambda (label) (list 'item label))
	       species))

-- 
Kevin Rodgers
Denver, Colorado, USA

Re: widget-create 'menu-choice

[Mortimer Cladwell]

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(apply 'widget-create 'menu-choice....
Will create multiple dropdown lists.  I want a single dropdown that has 
multiple elements.  I am thinking a macro is the way to go.  Consider:

(defmacro item-element (var)
           (list 'quote `'(item ,var)))

Then (item-element "human") would evaluate to (quote (item "human"))

What I haven't been able to do is mapcar item-element over my list

("rat" "human" "mouse")

The desired output is:

(quote (item "rat")) (quote (item "human")) (quote (item "mouse"))

Note the absence of circumscribed parenthesis, i.e. this is not a list.
Suggestions?
Thanks

Mortimer

----------------------------------------------------------

Mortimer Cladwell wrote:

Your suggestion evaluates to:
>> 
>((item "human") (item "rat") (item "mouse"))
>> 
>which when inserted into a form results in the error:
>> 
>widget-create: Invalid function: (item "human")
>
Ah, I misread the widget-create arguments.  That function's doc string is
practically useless.

Evaluations that would work are:
>> 
>'(item "human") '(item "rat") '(item "mouse")
>>OR
>
>(quote (item "human"))  (quote (item "rat")) (quote (item "mouse"))
>> 
Note that there are no enclosing parenthesis around the list.
>
As Andreas points out, you need apply:
(defvar species '("human" "rat" "mouse"))
(apply 'widget-create 'menu-choice :tag "Select Host Species" :value "unknown" :notify (lambda (widget &rest ignore) (setq host-species (widget-value widget))) (mapcar (lambda (label) (list 'item label)) species))
--
Kevin Rodgers
Denver, Colorado, USA


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