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From: Emanuel Berg <incal@dataswamp.org>
To: help-gnu-emacs@gnu.org
Subject: Re: macro that uses local variables
Date: Tue, 08 Aug 2023 03:27:22 +0200	[thread overview]
Message-ID: <871qgenx1h.fsf@dataswamp.org> (raw)
In-Reply-To: CTRcEs5TyCZ4Mr3zGFP_ALOdBI9eRrIgavhmOzTVcPCKA-Xg6a2L3-YDZsFiaX8E0QB0kGnnzbj59f_KsIucZIG9HjsCUeBnZMYZUpVeCd0=@protonmail.com

Heime wrote:

> I am using the rocket equation in this macro [...]
> 
> (defmacro booster-velocity-change
>     (specific-impulse standard-gravity initial-mass final-mass)
>   "Compute change of velocity using rocket equation."
>   `(* (* ,specific-impulse ,standard-gravity)
>         (log (mass-ratio ,initial-mass ,final-mass))) )

There is no reason to write a macro for this
simple computation.

> I want to change it such that the arguments are set as local
> variables

Lexical scope, defun, arguments, if need be `let'. It is
super easy.

If you start thinking "how do I solve my problem?" instead of
"how do I do <something> in Emacs", everything will be much
easier for you ...


-- 
underground experts united
https://dataswamp.org/~incal




  reply	other threads:[~2023-08-08  1:27 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-08  0:32 macro that uses local variables Heime
2023-08-08  1:27 ` Emanuel Berg [this message]
2023-08-09  3:09   ` Heime
2023-08-09 21:02     ` Emanuel Berg

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