From: "Tom Breton (Tehom)" <email@example.com> To: Carsten Dominik <firstname.lastname@example.org> Cc: email@example.com Subject: Re: Docs submitted (Was Re: Advice sought on managing decision alternatives.) Date: Wed, 11 Feb 2009 15:02:23 -0500 (EST) [thread overview] Message-ID: <firstname.lastname@example.org> (raw) In-Reply-To: <3AFEF956-A0A1-4777-B02C-4ECC58844EDB@uva.nl> > > Hi Tom, > > maybe you can educate me: I have never understood what the "#" does > in code like the one you have here. You are using it, so maybe you > know? > > - Carsten > > Here, it's #' that it of interest, not # alone. At the most direct level, it quotes the symbol with `function' instead of `quote'. For example: (format "%s" ' 'foo) => "(quote foo)" (format "%s" ' #'foo) => "(function foo)" What it accomplishes: * In some contexts, it is needed to get a symbol's function binding instead of its value binding. * It alerts the byte-compiler that it's seeing a function, so it can perform certain optimizations (I don't know offhand exactly what). * Stylistically, it alerts the reader. It's an imitation of Common Lisp's reader macro #' which does sort of the same thing. At the syntax level, it's really a combination of # which signals a reader macro - though in emacs, it's all hard-coded and inextensible - and ' which stands for the function-quote reader macro. FWIW, what I added to lread.c was an extension of the reader macro facility at RMS' request, so you definitely asked the right guy. Tom Breton (Tehom)
next prev parent reply other threads:[~2009-02-11 20:02 UTC|newest] Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <20090101170227.C707734803@mail2.panix.com> 2009-01-01 22:53 ` Feature request and patch - blocked TODO to say BLOCKED Tom Breton (Tehom) 2009-01-09 8:16 ` Carsten Dominik 2009-01-15 2:34 ` Tom Breton (Tehom) 2009-01-17 8:01 ` Carsten Dominik 2009-01-19 3:33 ` Advice sought on managing decision alternatives Tom Breton (Tehom) 2009-01-22 11:15 ` Carsten Dominik 2009-01-31 4:21 ` Tom Breton (Tehom) 2009-01-31 5:41 ` Carsten Dominik 2009-01-31 18:36 ` Tom Breton (Tehom) 2009-02-01 15:54 ` James TD Smith 2009-02-06 13:08 ` Carsten Dominik 2009-02-06 16:16 ` William Henney 2009-02-06 20:07 ` Tom Breton (Tehom) 2009-02-07 0:18 ` Carsten Dominik 2009-02-07 20:46 ` Tom Breton (Tehom) 2009-02-08 13:06 ` Carsten Dominik 2009-02-08 20:25 ` Tom Breton (Tehom) 2009-02-09 6:42 ` Carsten Dominik 2009-02-10 3:14 ` Docs submitted (Was Re: Advice sought on managing decision alternatives.) Tom Breton (Tehom) 2009-02-10 7:55 ` Carsten Dominik 2009-02-24 0:51 ` org-choose bugfix Tom Breton (Tehom) 2009-02-24 3:05 ` Manish 2009-04-07 0:13 ` Tom Breton (Tehom) 2009-04-08 13:13 ` Carsten Dominik 2009-02-24 5:51 ` Carsten Dominik 2009-02-10 8:46 ` Docs submitted (Was Re: Advice sought on managing decision alternatives.) Manish 2009-02-10 9:12 ` Carsten Dominik 2009-02-10 10:26 ` Manish 2009-02-10 22:48 ` Tom Breton (Tehom) 2009-02-12 12:50 ` Manish 2009-02-12 20:13 ` Tom Breton (Tehom) 2009-02-13 4:23 ` Manish 2009-02-12 20:55 ` Patch " Tom Breton (Tehom) 2009-02-13 4:38 ` Manish 2009-02-11 1:08 ` Tom Breton (Tehom) 2009-02-11 10:34 ` Carsten Dominik 2009-02-11 21:41 ` Tom Breton (Tehom) 2009-02-11 23:38 ` Nick Dokos 2009-02-12 4:17 ` Tom Breton (Tehom) 2009-02-11 23:44 ` Carsten Dominik 2009-02-12 4:27 ` Tom Breton (Tehom) 2009-02-12 15:49 ` Nick Dokos 2009-02-12 20:32 ` Tom Breton (Tehom) 2009-02-12 21:25 ` Nick Dokos 2009-02-11 12:29 ` Carsten Dominik 2009-02-11 14:58 ` Docs submitted Bernt Hansen 2009-02-11 17:33 ` Samuel Wales 2009-02-11 15:38 ` Docs submitted (Was Re: Advice sought on managing decision alternatives.) Daniel Clemente 2009-02-11 15:41 ` Carsten Dominik 2009-02-11 20:02 ` Tom Breton (Tehom) [this message] 2009-02-11 23:45 ` Carsten Dominik 2009-02-11 1:45 ` Slight fix to update-org.sh Tom Breton (Tehom) 2009-02-10 23:19 ` Docs submitted (Was Re: Advice sought on managing decision alternatives.) Tom Breton (Tehom) 2009-02-11 10:34 ` Carsten Dominik 2009-02-10 22:45 ` Tom Breton (Tehom)
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