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From: raman <raman@google.com>
To: Eric Abrahamsen <eric@ericabrahamsen.net>
Cc: emacs-devel@gnu.org
Subject: Re: defsubst VS defun or defmacro [was RE: Compiled code in Emacs-26 will fail in Emacs-25 if use pcase]
Date: Thu, 23 Feb 2017 19:56:19 -0800	[thread overview]
Message-ID: <p91o9xs6y3g.fsf@google.com> (raw)
In-Reply-To: <87mvdcfffg.fsf@pellet> (Eric Abrahamsen's message of "Thu, 23 Feb 2017 19:14:43 -0800")

The rule of thumb I've used over the years:

1. Never use defmacro except when creating a special-form or special
notation AKA DSL 

2. Use defun except for short and often repeated forms that also need
speed, then I've used defsubst because they behave like functions for
all practical purposes such as mapcar.

3. I had done some timing in the early days of emacspeak, including
looking at what M-x disassemble produced, then tighten the inner loop of
emacspeak appropriately with defsubst.

4. What just broke is  calls to defsubst-defined functions from within
other defsubst --- independent of our various views on the misguidedness
or otherwise of defsubst, I believe this is a bug that might be worth
fixing since it breaks  working code in mysterious and unpredictable ways.
-- 



  reply	other threads:[~2017-02-24  3:56 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-06 17:50 [PATCH]: Add new bytecode op `switch' for implementing branch tables Vibhav Pant
2017-02-06 18:30 ` Stefan Monnier
2017-02-07  8:45   ` Vibhav Pant
2017-02-07 14:41     ` Stefan Monnier
     [not found]       ` <CA+T2Sh3N09WGoHtNL3BbptsKA1ZdwWedTNDd0vmeBe0fTO5a1g@mail.gmail.com>
     [not found]         ` <CA+T2Sh2sa6=WOvyePzL_ACR0Nw=jTnZze_xXFcvL=22OURP=ZA@mail.gmail.com>
2017-02-07 15:21           ` Vibhav Pant
2017-02-07 13:50   ` Vibhav Pant
2017-02-07 15:56     ` Clément Pit-Claudel
2017-02-08 13:38       ` Vibhav Pant
2017-02-08 16:21         ` Vibhav Pant
2017-02-08 17:46           ` Vibhav Pant
2017-02-09 13:21           ` Stefan Monnier
2017-02-08 17:56         ` Eli Zaretskii
2017-02-23  4:35           ` Compiled code in Emacs-26 will fail in Emacs-25 if use pcase [was: Add new bytecode op `switch' for implementing branch tables.] Tino Calancha
2017-02-23  8:36             ` Richard Copley
2017-02-23 10:12               ` Tino Calancha
2022-07-04 12:24               ` Vibhav Pant
2017-02-23 13:39             ` Stefan Monnier
2017-02-23 14:33               ` Kaushal Modi
2017-02-23 15:10                 ` Stefan Monnier
2022-07-02 20:31                   ` Robert Weiner
2022-07-02 21:28                     ` Stefan Monnier
     [not found]               ` <CA+T2Sh29UhuNrhRZG=PPQbYYHtONXwyb8dX4rBVLmwdORLELhg@mail.gmail.com>
2017-02-23 17:50                 ` Vibhav Pant
2017-04-11 17:40               ` Compiled code in Emacs-26 will fail in Emacs-25 if use pcase Lars Brinkhoff
2017-02-23 16:15             ` Compiled code in Emacs-26 will fail in Emacs-25 if use pcase [was: Add new bytecode op `switch' for implementing branch tables.] raman
2017-02-23 17:24               ` Drew Adams
2017-02-23 17:50                 ` T.V Raman
2017-02-23 18:02                   ` Drew Adams
2017-02-23 18:24                     ` T.V Raman
2017-02-23 19:00                       ` Drew Adams
2017-02-24  2:06                       ` defsubst VS defun or defmacro [was RE: Compiled code in Emacs-26 will fail in Emacs-25 if use pcase] Tino Calancha
2017-02-24  3:14                         ` Eric Abrahamsen
2017-02-24  3:56                           ` raman [this message]
2017-02-24  4:20                             ` Eric Abrahamsen
2017-02-24  3:51                         ` raman
2017-02-09 17:32         ` [PATCH]: Add new bytecode op `switch' for implementing branch tables Clément Pit-Claudel
2017-02-09 19:15         ` Clément Pit-Claudel
2017-02-10  4:12           ` Vibhav Pant
2017-02-10  4:17             ` Clément Pit-Claudel
2017-02-10  5:03               ` Vibhav Pant
2017-02-10  6:07                 ` Stefan Monnier
2017-02-10 13:51                   ` Vibhav Pant
2017-02-10 15:12                     ` Stefan Monnier
2017-02-10 17:59                       ` Vibhav Pant
2017-02-10 18:25                         ` Vibhav Pant
2017-02-10 20:47                           ` Paul Eggert
2017-02-10 20:58                             ` Stefan Monnier
2017-02-11 15:07                             ` Vibhav Pant
2017-02-12  3:10                               ` Vibhav Pant
2017-02-13  7:18                                 ` Vibhav Pant
2017-02-09 16:37       ` Vibhav Pant
2017-02-06 19:32 ` Eli Zaretskii
2017-02-07 14:26   ` Vibhav Pant
2017-02-07 16:14     ` Eli Zaretskii

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