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Re: No cl-lib replacement for define-modify-macro?
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From: |
Stefan Monnier |
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Subject: |
Re: No cl-lib replacement for define-modify-macro? |
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Date: |
Tue, 06 Nov 2012 13:03:10 -0500 |
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User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.2 (gnu/linux) |
>> The replacement is gv-letplace.
> How do I write:
> (define-modify-macro incf (&optional (n 1)) +)
> using gv-letplace? (Forget about the "&optional" bit if necessary.)
Guaranteed 100% untested:
(defmacro incf (place &optional n)
(gv-letplace (getter setter) place
(macroexp-let2 nil v (or n 1)
(funcall setter `(+ ,v ,getter)))))
-- Stefan