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RE: emacs lisp - unable to write a function maker


From: Drew Adams
Subject: RE: emacs lisp - unable to write a function maker
Date: Fri, 16 Sep 2011 07:06:13 -0700

> if you're using eval on something you don't want eval'd
> until the function is run, you should backquote it.
> 
> (defun functionmaker (name form)
>   (eval `(defun ,name () ,form)))
> 
> I used to associate backquoting exclusively with macros, but I think
> that was wrong thinking.

Right.

But if you're evaluating the entire constructed form once at the top level like
that, then you likely do want to use a macro. That's just what a Lisp macro is:
a function that returns code that then gets evaluated.

(defmacro functionmaker (name form)
 `(defun ,name () ,form))

Or, for the original question:

(defmacro makeAbrevFun (name val)
 `(defun ,name () (insert ,val)))

(makeAbrevFun aa "aaaaaaaaaaaaaa")

Well, not quite - the OP quoted the function symbol, indicating that s?he would
pass something that needs to be eval'd. If that's rally part of the requirement,
then:

(defmacro makeAbrevFun (name val)
 `(defun ,(eval name) () (insert ,val)))

(makeAbrevFun 'aa "aaaaaaaaaaaaaa")

In both cases: (symbol-function 'aa) gives:
(lambda () (insert "aaaaaaaaaaaaaa"))




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