From: Ian Eure <ian@digg.com>
To: Andreas Politz <politza@fh-trier.de>
Cc: help-gnu-emacs@gnu.org
Subject: Re: Programmatically creating functions
Date: Sat, 25 Oct 2008 11:28:44 -0700 [thread overview]
Message-ID: <4F2314A6-3301-4113-8D13-182038727A3F@digg.com> (raw)
In-Reply-To: <1224615828.488025@arno.fh-trier.de>
On Oct 21, 2008, at 11:57 AM, Andreas Politz wrote:
> Joost Diepenmaat wrote:
>> Ian Eure <ian@digg.com> writes:
>>> So, I have a list of symbols:
>>>
>>> '(foo bar baz)
>>>
>>> I want to iterate over the list and create a function from each
>>> which
>>> does something like this:
>>>
>>> (defun call-foo ()
>>> (interactive)
>>> (invoke-stuff 'foo)
>>>
>>> How can I accomplish this? I can't figure out how to create the
>>> function. I've tried a number of approaches, but have not met with
>>> success.
>>>
>>> - eval'ing the defun. Returns a function symbol, but I can't call
>>> it. Maybe it's only created within the scope of the (eval) and not
>>> callable from outside?
>>>
>>> - Creating a symbol and using fset to assign a lambda to it's
>>> function cell. It sort of works, but I'm unclear on how to pass a
>>> variable function name to defun, nor am I clear on how I can make
>>> sure
>>> it calls invoke-stuff with the right symbol.
>> I'm not /quite/ sure where you've got problems, but in this case
>> elisp's
>> lack of closures hurts. IMHO the simplest way to get what you want
>> is to
>> use a macro:
>> (defmacro make-caller-macro (symbol) `(defun ,(intern (concat
>> "call-" (symbol-name symbol))) () (,symbol)))
>> But that won't evaluate the argument, so you'd more or less have to
>> use
>> eval as well:
>> (dolist (s '(foo bar)) (eval `(make-caller-macro ,s)))
>
>
> Does this work ? (in general)
>
Yes, with a little hacking, it works:
(defvar sql-connection-alist
'((poola
(sql-product 'mysql)
(sql-server "pool-a")
(sql-user "me")
(sql-password "mypass")
(sql-database "default")
(sql-port 3306))
(poolb
(sql-product 'mysql)
(sql-server "pool-b")
(sql-user "me")
(sql-password "mypass")
(sql-database "default")
(sql-port 3307)))
"AList of preset connections for `sql-connect-preset'.")
(defun sql-connect-preset (name)
"Connect to a predefined SQL connection listed in `sql-connection-
alist'"
(require 'sql)
(let ((conn (cdr (assoc name sql-connection-alist)))
(sql-name (symbol-name name)))
(eval `(let ,conn
(flet ((sql-get-login (&rest what)))
(sql-product-interactive sql-product))))))
(defun sql-convenience ()
(interactive)
(mapcar (lambda (conn)
(let ((name (car conn)))
(fset (intern (format "sql-%s" name))
`(lambda nil
,(format "Connect to %s SQL preset." name)
(interactive)
(sql-connect-preset ',name)))))
sql-connection-alist))
So now I can define preset connections and get sql-* methods to invoke
them directly.
Thank you for the help.
- Ian
next prev parent reply other threads:[~2008-10-25 18:28 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <mailman.1730.1224610023.25473.help-gnu-emacs@gnu.org>
2008-10-21 18:22 ` Programmatically creating functions aartist
2008-10-21 18:34 ` Joost Diepenmaat
2008-10-21 18:57 ` Andreas Politz
2008-10-25 18:28 ` Ian Eure [this message]
[not found] ` <mailman.2073.1224959342.25473.help-gnu-emacs@gnu.org>
2008-10-28 20:29 ` Emil
2008-10-21 17:26 Ian Eure
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