From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: defmacro with built-in gensym declaration and initialization Date: Thu, 21 Jan 2021 16:05:53 -0500 Message-ID: References: <87bldk6n2l.fsf@gmail.com> <87turbiuvr.fsf@tcd.ie> <878s8n76ih.fsf@gmail.com> <87o8hj9vl9.fsf@tcd.ie> <875z3q6q51.fsf@gmail.com> <875z3qc8ur.fsf@tcd.ie> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="21586"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) Cc: akater , emacs-devel@gnu.org To: "Basil L. 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Contovounesios's message of "Thu, 21 Jan 2021 20:50:52 +0000") Received-SPF: pass client-ip=132.204.25.50; envelope-from=monnier@iro.umontreal.ca; helo=mailscanner.iro.umontreal.ca X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:263255 Archived-At: >> Sorry, I suspect I misunderstood. What's a native arglist? Doesn't >> defmacro already have native support for &optional and &rest keywords? > Yes, and that's what I mean by native arglists - the ones possessed by > built-in C objects such as subroutines, lambda expressions, compiled > code, dynamic module functions, etc. and used by built-in C functions > such as funcall. > By contrast, cl-defmacro, other CL compatibility definitions, etc. have > to parse a plain Elisp arglist for CL-specific features like &aux. FWIW, `defmacro` is itself a macro, just like `cl-defmacro`, so it wouldn't be that terribly hard (the only problem is that it needs to be implemented without itself using macros, more or less). For me it's more a question that whatever something like `&gensym` can't use values that are computed during the macro expansion, , so (defmacro M (ARGS &gensym FOO) ...) is equivalent to something like: (defmacro M (ARGS) (with-gensyms (FOO) ...)) except: - it's a bit more concise - it exposes internal implementation details into the arglist, which is usually considered as part of the signature. - it doesn't cover the cases where you need `with-gensyms` deeper than at the toplevel of the macro's body. I find the added concision doesn't pay for the other two downsides. Stefan