Re: Future of LISP. Alternative to XML. Web 3.0?

Robert Maas, see http://tinyurl.com/uh3t wrote:

Just now, in preparation for responding to your posting.
It has some rough edges. For example, when I saw /<carriage-return>
I didn't realize it meant literally the cr character within the
message, I thought the textual string <carriage-return> literally
appeared, and I hoped it would be later explained *which* carriage
returns (later) would be ignored and when the ignoring of them
would be turned back off. Then the examples just had nothing at
all, just a new-line situation, with no explanation what was
supposed to be there. Apparently what's there is the option of the
local implementation, and regardless of which of the four choices
applies, a backslant at the end of the line causes that line to be
directly adjacent to the start of the next line ignoring whichever
of the four types of newline happened to be present. That ought to
be explained a little, instead of leaving it to the reader to guess
what is meant.
Also the BNF has semicolons at the ends of some lines but not
others, and I have no idea what those semicolons denote. I'm pretty
sure they aren't supposed to be literally present in the syntax
being defined?

Why do not ask him directly? http://theory.lcs.mit.edu/~rivest/

S-expr are more concise and easy to parse than XML. You would note
improvements when dealing with high volume traffic sites or
manipulating large files.

That's not the point I was making. If somebody implements a server
that merely duplicates an already-available service, except for
using s-expressions instead of XML, nobody is going to use it,
because it's cheaper to keep the existing XML software and continue
paying for extra bandwidth rather than rewrite all the software
just to save a fraction on the bandwidth.

This is a case-by-case. It depends of the cost of the XML software
being used and of the cost of the extra bandwidht and/or server disk
and processing time.

In [1] you can find an example of s-expr instead XML for military data.
He claims reduction in a factor of 4.

Others in newsgroup could offer you more help and examples that i can.

We need a brand-new service that somebody might want to use, which
isn't already provided via XML, so somebody would have incentive
play with it manually to get a feel for the service offered and to
*see* how incredibly more legible and significantly more efficient
it is compared to XML, and then having seen that they might be
willing to download our new s-expression plugin for
distributed-computing API so that their software could then use XML
or s-expressions equally. Note that our server could provide output
in three modes, fully prettyprinted, typical-compact prettyprinted,
and ultra-compact, making it easy to switch between
debugging/explanatory mode and maximal-efficient mode.

Something somewhat similar i am trying to do for CanonML for scientific
and mathematical data.

For instance, something like [a / 2] is left at editing and storing
mode (you call "ultra-compact"). At this representation one typically
saves 10x over typical XML encoding. Next, it can be parsed to [#fract
[#num a] [#den 2]] for 'prettyprinted'.

Current browsers do not understand this code, but is easily parsed to
XML-MAIDEN format [2] or to HTML format and next displayed via standard
CSS. The program is to continuum substitution of XML, HTML, CSS layers
for new CanonML layers.

As an alternative to a brand-new service, one hack I have been
thinking about from time to time is to get permission to use
Google's XML interface to their search engine, then write an
interface that maps between s-expressions and XML, so somebody
could connect to my CGI application, submit Google searches in
s-expression format, and get back RMI objects/references in
s-expression format, and then browse the RMI objects remotely via
my service. As a distributed application, for my own personal use,
I could write an s-expression client that submitted a Google search
via my s-expression interface, then browsed the resultset to
organize it better, then finally presents the nicely re-organized
index of search results as a tree of virtual Web pages for me to
browse from a regular Web browser.

I have in mind something similar except i would not convert to xml
format and that i would use cnml expresssions as input. When working,
it would do in any search engine, currently i am researching on the
surface of google, Yahoo!, and MSN engines.

I asked Google representative for specific support of metadata on their
scholar optimized engine but they recomend to me PDF format only for
online data, therein i am trying to develop a new search engine service
can access to metadata otherwise would be lost.

Do *any* of those LISP projects have a (HTTP-accessible) server I
can play with, to see their various encodings of XML, to compare
them?

Online search by SXML, DSSSL, GSXML, Latte, Scribe... LML, the HOP
project nayone cited here other day, and you can find useful
information about the s-expressions being used and lisp and scheme
sources to final html and xml docs togheter with apps and code for both
off and online conversions. DSSSL is a ISO standard. SXML approach is
very 'complete' including SSAX (Scheme) parsers, libraries, and
others...

There is too many information.

Do you really mean modification (incompatible changes), or merely
enhancements/additions?

Both. At Arc community you can find both people adding cosmetic changes
over a CL or Scheme basis and people going beyond.

3) Documentation. XML was designed for documents, S-expr for data.

But documents *are* (one kind of) data!

Yes, by document vs. data people mean mixed vs. pure data.

S-expressions have already been used to represent lots of different
kinds of data. Surely they can also represent documents.

Yes. You can also represent docs in stone. The point is that s-expr are
not optimal for documents, somewhat as XML is not optimal for data.

There are several documentation systems based in s-expr (e.g. Scribe),
but failed to be popular when compared with acceptance of HTML or TeX.

Both HTML and TeX suck when it comes to expressing mathematics.

Yes, but people has found both TeX and HTML more confortable than
s-expr for documentation purposes during decades. Scribe is even
previous to SGML!

Compare these two ways of expressing the same thing:
(expt (arrayelement x 5) 2)
x superscript 2 backspace subscript 5 endelement
Can you see that s-expressions clearly show the nesting of
mathematical notation, whereas TeX acts like a manual typewriter
moving head up or down with no reference to what the mathematics is
supposed to really mean?
2
x
5
Is that even possible to express in HTML?

In a tricky way? Yes. I use a cnml format next is converted to HTML at
_client_ for rendering. Using classes and storing the source in a title
or alt element, you can maintain semantics: title='(expt (arrayelement
x 5) 2)'

Of course, you cannot access to the information in a easy way and
information is not structured, therein tricky. At least i can offer
today more mathematical information is possible with TeX and MathML
approaches and information. Full approach would need of a XML browser
or a CanonML or LISP browser.

By the way, way back in 1975 I wrote a crude text-layout program
(MRPP3 a.k.a. POX, successor to something (MRPPP and MRPP2) I had
written in 1969-70), which had overlays (composible pieces of
picture which could then be combined in various geometric
arrangements to make larger pictures), and macros (syntax vaguely
like Algol/MacSyma when called, defined usually to build overlays
out of pieces). Bill Gosper wrote a dandy set of macros for his own
use, enabling him to use my program to lay out immense continued
fractions and matrices and hypergeometric series etc., not as
pretty font-wise as Knuth's carefully tuned Tex, but properly
structured per the nested mathematical expressions.

Later, using PSL (Portable Standard Lisp), I re-wrote the program
(now MRPP4) to work directly from Lisp nested-lists, basically
using the same internal representation as Tony Hearn's "Reduce",
producing output in several formats (ASCII-art, and IBM CRTs
attached to VM/CMS system, and Unix workstations using X),
including a visual interactive structure editor where the cursor
covered an entire sub-expression, shown as that part of the display
highlighted, and could be zoomed in or out and panned up or down
the current level of structure, and then a command could be
executed on the current sub-expression as embedded in the larger
expression to perform algebraic manipulations.

MacSyma used a vaguely similar internal representation to Reduce, a
bit more ugly in my opinion. But in any case, the basic idea is
that internal Lisp structures were used to represent mathematical
documents, and then of course PRINT could externalize such data and
READ could get stuff back in, and MRPP4 could render the data
structures in the usual mathematical-notation format. (MacSyma also
had a math-format display mode, which it normally used for all
output in the ordinary Read-MathEvaluate-Print loop. AFAIK MacSyma
display output provided *only* ASCII-art mode, but I'm probably
mistaken.)

Wow!

Anyway, one application I'm thinking of writing is a port of MRPP4
to CGI/CMUCL, whereby s-expressions from the client get
internalized to Lisp structures and then displayed as
MRPP4/MacSyma-style ASCII art, using <pre>...</pre> of course to
make sure things line up in all browsers.

Interesting! I decided do not use ASCII art. I use basic CSS+HTML
rendering techniques i adapted from XML-Maiden project to HTML, working
minimally for 'modern' Gecko, trident, and Opera engines (> 95%
clients). Very old browsers can still access the math but displaying
the source code. I work stuff as [Y = [a / 2]] but techniques can be
easily adapted to (= Y (/ a 2)).

Of course I'd also have
an output mode for box-diagrams showing how the internal data is
structured. The math-display output would work only for valid math
structures, whereas the box-diagrams would work for all Lisp data.

Interesting again, i plan an automatic tree drawing and also an first
class typesetting engine without TeX metrics not conventions for a
future.

For instance [a = [b + c]] i.e. (= a (+ b c)). TeX does not correclty
structure the maths, then the engine simply generates a sequence of
tokens a = b + c and next recognizes the + as special binary operator
and the = as special relation operator, checks some built-in metric
tables and adds automatic 4/18 and 5/18 spacing around operators
respectively.

This is time-consumming, obligate to store the metric table and assumes
meaning about symbols, e.g. asumes that = is operator equals when could
be not. Presentation MathML correct this and can differentiate beteeen
<mi>=</mi> and <mo>=</mo>.

I had thought of someting as direct rendering of underliyng nested
structure [a = [b + c]] where each box [ ] receive extra space around
it. This way the b got more space around the = than around the +. It is
automatic, display represents the nested structure, is cheap and
do not need of metric tables or predefined symbols. What do you think?

Indeed! With 100 proposed, I would expect to see live
Web-accessible demos of at least twenty of them already.
Do you know of any such?

Yes, i revised all of that in previous research. Several focus on some
subset as XSLT or XHTML. Other try to be alternative as data format
others focus on some specific point as non-hierarchies.

Most of them are accesible online and contain tutorials, sources...
Some of them are non-continued projects as Latte. Wikipedia works with
alternative to xhtml, YAML got popularity, last changes on LMNL were
presented in last Extreme markup conference (there is an online demo in
some place now i do not remember) Markdown is used in several blogs...
Please follows the links or Google a bit.

SXML provides a representation for XML documents in the Scheme
programming language -a kind of dialect of LISP-.
Is that really true, presumably some specialized Scheme notation
that is incompatible with Common Lisp?

I do not understand you, is true what?

I reserved the sequence :: for the tags because is "never" used in
real practice.

The :: notation is not more used switching to #, but this is not still
closed issue. The character is escaped when apearing.

At one point you said that [...] is more legible than (...), or
that's what you seemed to say.

More people said that, specially with ] begining a new line. I read
that people claiming square brackets as alternative to parentheses in
next Scheme. I read also several people claiming square brackets for
next Arc. Graham appears to like rounded ones.

Also many modern languages recently arised use [ ] for arrays and
lists. Logo also uses [ ]. On any case {} is characteristics of C and
TeX, and () is of LISP and SXML, therefore [] appears to be a good
option.

[1] http://okmij.org/ftp/Scheme/SXML-as-database.txt

[2] http://my.opera.com/White%20Lynx/blog/show.dml/256124

.

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