# Re: small questions regarding integrals


> Dave proposes something on the order of
>
>   integral from ... to ... of ... \d x
>
> for an "ordinary" integral.
>
> 1. How will we handle the variants on this theme such as multiple
> integrals (to be rendered with multiple integral signs), path
> integrals, etc. ?

Multiple integrals can be handled in several ways:

o   as a sequence of symbol names for single integral signs

o   using special symbol names, e.g. for an integral
over a closed path, surface or volume

> 2. Is there a specific reason we don't want to use the TeX-like
> notation: \int_{...}^{...} ... ?  (because the _ and ^ operators

The benefits of an extensible language is that we don't need to
decide this now. One could specify _' as a lowering operator
and ^' as a raising operator that when applied to integral signs
denote limits of integration. This is a matter for the rules that
map the stream of lexical tokens into a semantic description of
that input. These rules can be extended by authors.

\int' versus integral is a question of style. We have discussed
whether the notation should lexically distinguish operators from
identifiers. But the \' character as a prefix is unlikely to be
sufficient for this, as one may want to use it for other purposes
e.g. greek letters, or language directives.

The {' and }' characters are special, however, e.g. they must
always match (unlike other bracket symbols), and that they act
as invisible brackets, as in TeX.

We have agreement on some of the details of what constitutes lexical
tokens in the notation. I need to write this up in more detail, based
on messages in the list archive. For example identifiers may consist
of more than one character.

-- Dave Raggett <dsr@w3.org> tel: +1 (617) 258 5741 fax: +1 (617) 258 5999
World Wide Web Consortium, 545 Technology Square, Cambridge, MA 02139
url = http://www.w3.org/People/Raggett



Follow-Ups:
References: