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From: Stefan Monnier <monnier@iro.umontreal.ca>
To: Jose A Ortega Ruiz <jao@gnu.org>
Cc: emacs-devel@gnu.org
Subject: Re: [nongnu] elpa/geiser bb9d5cb200: geiser-impl--normalize-method: quick fix for previous change
Date: Fri, 28 Jan 2022 16:16:54 -0500	[thread overview]
Message-ID: <jwva6ff602p.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <87bkzva8qh.fsf@gnus.jao.io> (Jose A. Ortega Ruiz's message of "Fri, 28 Jan 2022 20:47:02 +0000")

> yes, that works, but i find it ugly to use eval explictly for the sake
> of not using "a list-that-looks-like-a-function":

To me, it's being more honest: we have a variable that holds an ELisp
expression, so we need `eval` somwehere.

> what are the downsides of the latter?  i understand that i'd be just
> hiding an implicit eval, but is that all, or am i missing
> other drawbacks?

There's no serious drawback, no.  Here are some minor drawbacks:
- In Common-Lisp and Scheme '(lambda () 5) does not evaluate to
  something recognized as a function.  Currently ELisp does, but I think
  it's something better avoided.  I hope in some distant future we can
  make the types `function` and `cons` be a mutually-exclusive.
- the function value `(lambda () ,v) returns a function that will
  evaluate v using the old dynamically-scoped dialect which we're trying
  to phase out.

> (isn't, loosely speaking, hiding evals one of things macros
> buy us?

`eval` is used sometimes in macros, but most macros neither use nor hide
`eval`, AFAIK, no.

> ... the version without eval looks more readable to me).

My own taste is reflects in the fact that my local Emacs rejects
(lambda ...) as a valid function value ;-)


        Stefan




  reply	other threads:[~2022-01-28 21:16 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <164339989485.1614.11034229578358286224@vcs2.savannah.gnu.org>
     [not found] ` <20220128195815.4DB24C423B9@vcs2.savannah.gnu.org>
2022-01-28 20:16   ` [nongnu] elpa/geiser bb9d5cb200: geiser-impl--normalize-method: quick fix for previous change Stefan Monnier
2022-01-28 20:47     ` Jose A Ortega Ruiz
2022-01-28 21:16       ` Stefan Monnier [this message]
2022-01-28 23:07         ` Jose A Ortega Ruiz

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