Re: Syntax trees, macros, and reflexive Lua evolution

["Dr. Rich Artym" <rartym@...>]

On Tue, Nov 09, 2004 at 05:40:37PM +0200, Asko Kauppi wrote:

> Could you please explain to us to-be-doctors, what you mean by:
> 
>> Wholesale attachment to a 1-dimensional textual representation is
>> rather bizzare, when you think about it, and my guess is that it will
>> disappear entirely once programming attains some sort of maturity.

That was just a reference to comp lang grammars traditionally parsing a
single long string of characters (hence 1-dimensional) as input.  This is
not a required property of syntactic parsing, ie. you can perfectly well
define a grammar over any object set you like, not just characters, and
in as many dimensions as you like, not just one.

Looking ahead, the 1-dimensional plain text is more a hindrance than an
asset for machine processing, and since we're highly likely to become
programming orchestrators rather than direct programmers in the future,
it seems to me that the 1D textual form has a pretty limited lifespan.

Of course, those who use app structure editors could validly claim that
the future is already here, but just hasn't caught on in programming.
That would be hard to dispute. :-)

All this was an aside though, and it applies to LISP as much as it does
to Lua and all other normal languages.  Where there is a key difference
is in the fact that there is almost no barrier at all to interning the
unhelpful 1D textual S-expressions into an extremely helpful directly
manipulable tree.

In contrast, most other languages either present a sizeable hurdle to
such processing or, more often than not, disallow manipulation of the
program by the program entirely.  Lua lies somewhere in the middle, in
lacking an official interned form yet happily compiling new linguistic
input at runtime.  This is sheer pragmatism at work though, and very
useful pragmatism it is, but it's never been seriously suggested as a
mechanism for machine processing of Lua's program graph, afaik.

Rich Artym.
-- 
Existing media are so disconnected from reality that our policy debates
spin around a fantasy world in which the future looks far too much like
the past.   http://www.zyvex.com/nanotech/MITtecRvwSmlWrld/article.html