From: Michael Heerdegen <michael_heerdegen@web.de>
To: Emacs Development <emacs-devel@gnu.org>
Subject: pcase: Semantics of atom QPATS
Date: Sun, 10 Jun 2018 02:40:08 +0200 [thread overview]
Message-ID: <87tvqbjwyf.fsf@web.de> (raw)
Hello,
isn't it strange that the pattern '.7 matches .7, but `.7 causes an
error when used?
Or
(pcase '(.7 1)
('(.7 1) t))
==> t
but
(pcase '(.7 1)
(`(.7 ,_) t))
|-- error: `--pcase-macroexpander: Unknown QPAT: 0.7
IMO the analogy to the list of self-quoting atoms (strings, keywords,
integers - I'm all for that) is misguided here - something implicitly
quoted in a backquoted pattern (i.e. something that is not unquoted)
should behave like quoted with `'' (i.e. transformed into an `eq' test),
everything else feels inconsistent.
This corner case actually bit me when I was trying to refactor a piece
of code that included the atom .7 (as you might have guessed) with
el-search.
Thanks,
Michael.
next reply other threads:[~2018-06-10 0:40 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-10 0:40 Michael Heerdegen [this message]
2018-06-11 14:09 ` pcase: Semantics of atom QPATS Stefan Monnier
2018-06-11 14:45 ` Drew Adams
2018-06-11 15:24 ` Stefan Monnier
2018-06-11 20:53 ` Michael Heerdegen
2018-06-13 3:41 ` Michael Heerdegen
2018-06-13 12:52 ` Stefan Monnier
2018-06-16 4:03 ` Michael Heerdegen
2018-06-16 6:57 ` Eli Zaretskii
2018-06-16 7:32 ` Michael Heerdegen
2018-06-16 7:49 ` Eli Zaretskii
2018-06-17 13:35 ` Michael Heerdegen
2018-06-16 13:42 ` Noam Postavsky
2018-06-16 12:57 ` Stefan Monnier
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