What is PI data exactly?

Rick Jelliffe ricko at allette.com.au
Fri Oct 16 11:28:21 BST 1998

> From: owner-xml-dev at ic.ac.uk [mailto:owner-xml-dev at ic.ac.uk]On Behalf Of
> Michael Kay

> From: John Cowan >
> >> So if a PI has a target and data, what is the data in the following
> scenarios?
> >>
> >> <?Foo?>
> >> <?Foo     ?>
> >>
> >> Is the first null data and the second a string of spaces?
> >
> >The first case is definitely null data.  Production 16 says that
> >the optional data is prefixed by one or more whitespace characters
> >which are not part of it
> Are you reading the same spec as me?

As a side note, if you want to send whitespace in a PI, then you should not
	<?Foo  ?>
	<?Foo " "?>
or something similar, according to whatever tokenizing notation you define
for Foo.

Processing instructions should use some processing instruction language,
i.e. one which is tokenized with spaces and delimiters, as is ubiquitous.
They were not designed to transport "data" which could include significant
initial spaces. IMHO, people should try to use attribute syntax and
conventions if at all possible.

Rick Jelliffe

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