`'#@, s-expression syntax

[Tim Johnson]

Tried googling the following:
`'#@,
Not too much luck.
I could just use to pointers to URLs or docs on these symbols.
Also, keywords that refer to them
Thanks
Tim
--
Tim Johnson <t...@johnsons-web.com>
http://www.alaska-internet-solutions.com

[Rob Warnock]

Tim Johnson <t...@johnsons-web.com> wrote:
+---------------

| Tried googling the following:
| `'#@,
| Not too much luck.

+---------------

Because Google *deletes* such "punctuation" from search terms!! :-{

+---------------

| I could just use to pointers to URLs or docs on these symbols.

+---------------

First go find some version of the CLHS ("Common Lisp HyperSpec"), e.g.:

http://www.lispworks.com/reference/HyperSpec/Front/index.htm

Then click on the "Master Index" icon, then on the "Non-Alphabetic"
link, and browse the left-most character on each line.

But before you do that, you might find it more helpful to obtain a
somewhat higher-level view of the Common Lisp reader:

http://www.lispworks.com/documentation/HyperSpec/Body/02_b.htm
2.2 Reader Algorithm
This section describes the algorithm used by the Lisp reader to
parse objects from an input character stream, including how the
Lisp reader processes macro characters. ...

http://www.lispworks.com/documentation/HyperSpec/Body/02_d.htm
2.4 Standard Macro Characters

http://www.lispworks.com/documentation/HyperSpec/Body/02_dh.htm
2.4.8 Sharpsign

-Rob

-----
Rob Warnock <rp...@rpw3.org>
627 26th Avenue <URL:http://rpw3.org/>
San Mateo, CA 94403 (650)572-2607

[Alan Crowe]

rp...@rpw3.org (Rob Warnock) writes:

> Tim Johnson <t...@johnsons-web.com> wrote:
> +---------------

> | I could just use to pointers to URLs or docs on these symbols.
> +---------------
>
> First go find some version of the CLHS ("Common Lisp HyperSpec"), e.g.:
>
> http://www.lispworks.com/reference/HyperSpec/Front/index.htm
>
> Then click on the "Master Index" icon, then on the "Non-Alphabetic"
> link, and browse the left-most character on each line.
>
> But before you do that, you might find it more helpful to obtain a
> somewhat higher-level view of the Common Lisp reader:
>
> http://www.lispworks.com/documentation/HyperSpec/Body/02_b.htm
> 2.2 Reader Algorithm

Then have a play at the REPL

#' and ' are abbreviations, but the data denoted by the
abbreviations are printed out in using abbreviations, so you
cannot see what they are abbreviations for. Turning off the
pretty printer with :pretty nil gets round this.

CL-USER> (defparameter form (read))
(#'(setf foo) `(this that))
FORM

CL-USER> (write form :pretty nil)
((FUNCTION (SETF FOO)) (QUOTE (THIS THAT)))
(#'(SETF FOO) '(THIS THAT))

Some input needs to be accompanied by escape characters to
stop it being processed in the default manner. When the
input is printed out again, the printer adds the escape
characters back in. This is good because it permits
round-tripping: you can print things out and read them back
in. This is bad because you cannot see your actual input: it
comes out decorated with escape characters. Turning off the
escaping with :escape nil helps you see what is going on.

CL-USER> (defparameter strings-and-symbols (read))
("ab\"cd" |foo| foo)
STRINGS-AND-SYMBOLS

CL-USER> (write strings-and-symbols :escape nil)
(ab"cd foo FOO)
("ab\"cd" |foo| FOO)

Alan Crowe
Edinburgh
Scotland

[Tim Johnson]

Thanks a lot...
Much obliged.
tim

[William Bland]

On Tue, 07 Mar 2006 21:42:35 -0600, Rob Warnock wrote:

> Tim Johnson <t...@johnsons-web.com> wrote:
> +---------------
> | Tried googling the following:
> | `'#@,
> | Not too much luck.
> +---------------
>
> Because Google *deletes* such "punctuation" from search terms!! :-{

LispDoc also does rather badly with these (although not as badly as
Google). No reason why I can't improve it though - I've added this to the
TODO list.

Best wishes,
Bill.