[gobo-eiffel-develop] CAT calls caused by XML library

[Hiebert, D. \(MS\) <Dar...@ng...>]

I have discovered that the element and attribute name objects returned
by the 'name' queries of XM_ELEMENT and XM_ATTRIBUTE are of type
UC_UTF8_STRING when using the XM_EXPAT_PARSER. While a proper descendent
of the STRING type of these name queries, it creates the possibility of
CAT calls. Consider the following snippet of code:

My_attribute: STRING is "mine"

foo (att: XM_ATTRIBUTE) is
	local
		s: STRING
	do
		s :=3D att.name
		if s.is_equal (My_attribute) then
			...
		end
	end

This piece of code crashes with a segmentation violation in
UC_STRING.is_equal while evaluating its "trichotomy" postcondition,
because it believes the type of 'other' is "like Current", causing it to
crash when it cannot look up the '<' function of 'other'.

The 'name' queries return objects of type STRING when using the
XM_EIFFEL_PARSER.

I do not think there is a way to write code that will work correctly
with both parsers, as I have to be doing many string comparisons as
above with objects that are of nominal type STRING, but may actually be
descendents.

--
Darren Hiebert
Northrop Grumman
XonTech Systems Engineering
Phone: 256-705-0123