xml-dev - Why not PI's?

["Paul W. Abrahams" <abrahams@valinet.com>]

Norman Walsh wrote:

> / "Paul W. Abrahams" <abrahams@valinet.com> was heard to say:
> | I like the idea of what you're trying to do, but giving particular PIs an
> | essential function in XML seems to me the wrong way to go.
>
> Can someone point me to some arguments against PIs? There seems to be
> strong sentiment against them, and I don't understand why. Some things
> are exactly that, expectations that you wish to pass on to a processor.

I see PIs as something you wish to pass on to a particular processor or class
of processors.   My sense of the matter (admittedly, unsupported by any
documents I know of) is that they are, or ought to be, inessential to the
general interpretation of a document.   In other words, a well-formed and
valid document ought to remain well-formed and valid if all PIs are omitted.

Examples of PIs would be an indication that the following space character
should be non-breaking or that a page break would be desirable at this
point.   These would be "tweaks" in the form of typographical hints, quite
possibly particular to a specific version of a document typeset with one
specific typesetting program, e.g., TeX.

Paul Abrahams