# [TxMt] LaTeX grammer for subscript

Tue Nov 13 11:52:35 UTC 2007

Guido, I think the grammar you should be adding these constructs to
is the TeX Math grammar, since that is the main one that takes effect
in math mode.
The difference between $self and$base is indeed a delicate one, and
the choices we've made are perhaps not always the same. In this case,
I think the question is: Should we be allowing arbitrary LaTeX syntax
rules inside a math environment? For instance, should we recognize a
"\begin{document}...\end{document}" block within a math environment?
We opted for "no".

Best,
Department of Mathematics and Computer Science
Hanover College

On Nov 13, 2007, at 3:39 AM, Guido Governatori wrote:

>
> On 13/11/2007, at 4:04 PM, Allan Odgaard wrote:
>
>> On 12 Nov 2007, at 06:17, Guido Governatori wrote:
>>
>>> [...]
>>> Maybe I have not understood how include, but if I write a grammar
>>> where patterns contains only an include statement, don't I
>>> "create a copy" of the included grammar under a different name?
>>
>> Well, you include it, yes.
>>
>
> Allan, thanks for the explanation.
>
>> But if the included grammar does something like “begin = '$$'; end >> = '$$'; patterns = ( … );” then the rules you put in the grammar
>> where you include the former, will not be active inside (…).
>
> I did some experiments, and it seems that it depends whether the
> inner patterns (...) includes itself or not. Better, if it only
> includes itself (i.e., $self), then the definition external to the > include are not considered in the patterns; if it uses includes = > '$base' the external definitions are parsed inside the inner patterns.
>
>> Since LaTeX does a lot of this nesting of rules, it is generally
>> not possible to add a new rule then include the old grammar, and
>> expect the new rule to work in all contexts.
>
> I see that in some cases text.tex includes with $self. So scopes > with$self cannot be extended while scopes with base can.
>
> All the best
>
> Guido
> --
> Dr Guido Governatori
> School of Information Technology and Electrical Engineering
> The University of Queensland
> Brisbane, Queensland, 4072, Australia
> Phone: +61-(0)7-336 52907
> Fax: +61-(0)7-336 54999
> http://www.governatori.net/TextMate
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