From: Oleh Krehel <ohwoeowho@gmail.com>
To: Marcin Borkowski <mbork@mbork.pl>
Cc: Org-Mode mailing list <emacs-orgmode@gnu.org>
Subject: Re: Why does evaluating a piece of Elisp code seemingly not expand a macro?
Date: Fri, 15 Jan 2016 11:57:17 +0100 [thread overview]
Message-ID: <878u3rcdpu.fsf@gmail.com> (raw)
In-Reply-To: <87a8o7duj6.fsf@mbork.pl> (Marcin Borkowski's message of "Fri, 15 Jan 2016 11:08:45 +0100")
Marcin Borkowski <mbork@mbork.pl> writes:
> Why?
Macro-expand the defun to get:
(defalias 'print-answer
#'(lambda nil
(message
"The answer is %s."
(forty-two))))
`lambda' is a macro that /quotes/ its body. Therefore, the body of
`defun' is not evaluated or expanded when it's defined.
You probably wanted something like this instead:
(macroexpand-all
'(lambda nil
(message
"The answer is %s."
(forty-two))))
;; =>
;; (function
;; (lambda nil
;; (message
;; "The answer is %s."
;; 42)))
Which could be wrapped in a new macro:
(defmacro defun-1 (name arglist &optional docstring &rest body)
(unless (stringp docstring)
(setq body
(if body
(cons docstring body)
docstring))
(setq docstring nil))
(list 'defun name arglist docstring (macroexpand-all body)))
The above seems to work, at least superficially:
(symbol-function
(defun-1 print-answer ()
(message "The answer is %s." (forty-two))))
;; =>
;; (lambda nil
;; (message
;; "The answer is %s."
;; 42))
By the way, it might be more appropriate to ask similar questions on
help-gnu-emacs@gnu.org.
Oleh
next prev parent reply other threads:[~2016-01-15 10:57 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-15 10:08 Why does evaluating a piece of Elisp code seemingly not expand a macro? Marcin Borkowski
2016-01-15 10:57 ` Oleh Krehel [this message]
2016-01-17 22:56 ` Marcin Borkowski
2016-01-18 13:54 ` Stefan Monnier
2016-01-18 20:03 ` Marcin Borkowski
2016-01-18 20:19 ` Stefan Monnier
2016-01-15 21:10 ` Samuel W. Flint
2016-01-15 22:06 ` Nick Dokos
2016-01-15 22:24 ` Marcin Borkowski
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