Re: [NTG-context] What happened with sectionworld?

29 Apr 2009

      On Wed, Apr 29, 2009 at 6:46 PM, R. Bastian  wrote:
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On Wed, 29 Apr 2009 17:55:05 +0200
luigi scarso  scribit:
...
...
May be that ConTeXt is not a 'context free language'  ;-)
than it will be difficult to express something in a BNF grammar
http://en.wikipedia.org/wiki/Backus-Naur_form.
hmm.
Context is a macro package in TeX language which is Turing Complete.
...
But if (ConTeXt == formal_language), it should be possible to
develop TEXT, NUMBER, DIMENSION, REFERENCE, etc
and also to add examples for "[optional user data]".
hmm
I'm not sure that ConTeXt == TeX (but it seems YES) ,
I'm nor sure that TeX is a context free language too,
in the sense that I never see a BNF grammar of TeX .
(chap.24-26 of the Texbook are embryos of a grammar, but they are not
usable
like the grammar of Pascal or Python)
I suspect that TeX is not a cfl .
Anyway,
lpeg can make the thing easier
--
luigi

...
I think that something user-friendly could be do in a cooperative wiki (in
the between, i found
http://texshow.contextgarden.net/) beginning with
CONTEXT_SOURCE ::= PREAMBLE "\starttext" TEXT "\stoptext" | CONTEXT_SOURCE
TEXT ::= STARTSTOPS | SETUPS | DEFINES | OTHERS [ TEXT
and so on.
Consider that one can always make some dirty tricks in PREAMBLE to render
useless
"\starttext"
or "\stoptext"

To be general, i think
MY_CONTEXT_SOURCE ::= MACRO* END

For example , let's try
$>context test
where
test.tex ::="\end"
or
test.tex ::="FOO\end"

Are there any errors ? No
Is test.tex  in {CONTEXT_SOURCE } ? No
Is test.tex in {MY_CONTEXT_SOURCE} Yes
so MY_CONTEXT_SOURCE includes CONTEXT_SOURCE
(of course
test.tex ::="\end""\starttext""\stoptext" is also in {CONTEXT_SOURCE }
)

I think that a bnf or lpeg grammar is really useful for a sort of
standard-ConTeXt
or minimal-ConTeXt or light-ConTeXt
ie a ConTeXt to use as "reference"
but can be a bit hard to define

-- 
luigi