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From: Andreas Schwab <schwab@linux-m68k.org>
To: Juanma Barranquero <lekktu@gmail.com>
Cc: Bastien <bzg@gnu.org>, emacs-devel@gnu.org
Subject: Re: Why (substring "abc" 0 4) does not return "abc" instead of an error?
Date: Mon, 16 Jul 2012 09:38:47 +0200	[thread overview]
Message-ID: <m2ipdoyx2w.fsf@igel.home> (raw)
In-Reply-To: <CAAeL0STZCHYtchx4UG9fgTyrpcgPXFuVV=8mgFHzb0ntz3z74w@mail.gmail.com> (Juanma Barranquero's message of "Mon, 16 Jul 2012 02:10:37 +0200")

Juanma Barranquero <lekktu@gmail.com> writes:

> BTW, for unexpected behavior wrt strings, my favourite is this one
> (it's not a bug);
>
> (let ((s "ab") (m 2)) (eq (substring s 0 m) (substring s 0 m))) => nil
> (let ((s "ab") (m 1)) (eq (substring s 0 m) (substring s 0 m))) => nil
> (let ((s "ab") (m 0)) (eq (substring s 0 m) (substring s 0 m))) => t

That's not much different from ("foo" == "foo") in C.  Using eq for
comparing non-atoms is seldom useful.

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."



  parent reply	other threads:[~2012-07-16  7:38 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-15 23:15 Why (substring "abc" 0 4) does not return "abc" instead of an error? Bastien
2012-07-15 23:29 ` Juanma Barranquero
2012-07-15 23:59   ` Bastien
2012-07-16  0:10     ` Juanma Barranquero
2012-07-16  7:14       ` Bastien
2012-07-16 16:15         ` Stefan Monnier
2012-07-16 16:22           ` Bastien
2012-07-16 16:46           ` Bastien
2012-07-16 17:57             ` Tassilo Horn
2012-07-16 18:51               ` Lars Magne Ingebrigtsen
2012-07-16 19:30                 ` Bastien
2012-07-16 19:30                 ` Tassilo Horn
2012-07-16 20:20                 ` Pascal J. Bourguignon
2012-07-16 19:25               ` Bastien
2012-07-16 19:43                 ` Bastien
2012-07-16 20:19             ` Pascal J. Bourguignon
2012-07-16 20:30             ` Stefan Monnier
2012-07-16 22:28               ` Lennart Borgman
2012-07-16 22:48                 ` Bastien
2012-07-16 22:53                   ` Lennart Borgman
2012-07-16  7:38       ` Andreas Schwab [this message]
2012-07-16  9:40         ` Juanma Barranquero
  -- strict thread matches above, loose matches on Subject: below --
2012-07-16  3:45 Dmitry Gutov
2012-07-16  7:32 ` Bastien
2012-07-16  7:52   ` Thierry Volpiatto
2012-07-16  8:38     ` Bastien
2012-07-16 13:03   ` Dmitry Gutov
2012-07-16 14:32     ` Bastien
2012-07-16 13:10 ` Pascal J. Bourguignon
2012-07-16 14:40   ` Bastien
2012-07-16 15:00     ` Pascal J. Bourguignon
2012-07-16 15:07       ` Lennart Borgman
2012-07-16 15:19         ` Pascal J. Bourguignon
2012-07-16 15:22         ` Bastien
2012-07-16 15:46       ` Bastien
2012-07-16 15:49         ` Bastien
2012-07-16 19:49           ` Thien-Thi Nguyen
2012-07-16 22:32             ` Bastien
2012-07-16 15:56         ` Pascal J. Bourguignon
2012-07-16 16:13           ` Bastien
2012-07-16 19:00 Dmitry Gutov
2012-07-16 19:51 ` Tassilo Horn

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