From: Stefan Monnier <monnier@iro.umontreal.ca>
To: Naoya Yamashita <conao3@gmail.com>
Cc: emacs-devel@gnu.org
Subject: Re: [PATCH] * src/eval.c: Stop checking for nvars, and use only CONSP
Date: Mon, 01 Mar 2021 21:48:13 -0500 [thread overview]
Message-ID: <jwv4khunumk.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <20210302.111043.609653289571449353.conao3@gmail.com> (Naoya Yamashita's message of "Tue, 02 Mar 2021 11:10:43 +0900 (JST)")
> I found src/eval.c (let) has redundant conditions, that compares
> the length of the list with the current index and also checks if
> the current list is cons.
The patch looks fine, thank you.
Just one detail about the tests: the change you made affects the
evaluation of `let` in the case where the code is interpreted but it
is not used when the code is byte-compiled. So you might like your
tests to use things like
(eval '(let ...) t)
to avoid the compiler getting in the way.
> + ;; (error "`let' bindings can have only one value-form" a 1 2)
> + (should-error (let ((a 1 2))
> + a)
> + :type 'error)
Also, while this `let` is indeed invalid code, I don't think we
guarantee that it will signal an error, and especially not at runtime
(it's more likely to signal an error at macroexpansion or compile
time).
I think the compiler (or `macroexpand-all`) should make an effort to
detect and diagnose those problems, but I don't think it's important to
catch those problems in the interpreter.
Stefan
next prev parent reply other threads:[~2021-03-02 2:48 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-02 2:10 [PATCH] * src/eval.c: Stop checking for nvars, and use only CONSP Naoya Yamashita
2021-03-02 2:48 ` Stefan Monnier [this message]
2021-03-02 3:09 ` Naoya Yamashita
2021-03-02 14:31 ` Stefan Monnier
2021-03-02 15:19 ` Pip Cet
2021-03-02 15:48 ` Stefan Monnier
2021-03-02 17:04 ` Pip Cet
2021-03-02 17:44 ` Stefan Monnier
2021-03-02 19:50 ` Pip Cet
2021-03-02 23:48 ` Stefan Monnier
2021-03-02 5:34 ` Pip Cet
2021-03-02 5:41 ` Eli Zaretskii
2021-03-02 7:14 ` Naoya Yamashita
2021-03-02 7:30 ` Pip Cet
2021-03-02 14:00 ` Eli Zaretskii
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