I think I have the problem nailed down to the fact that in the comparison:
something >= -1234
the parser in question separates the minus in the negative number into a
separate child node, apart from the digits; witness the errormessage in the log
below.
Changing the number -1234 in the arithmetic expression to number("-1234")
(mind the quotes) does give a correctly evaluated expression.
Still, I am baffled by the fact that in arithmetic expressions positive and
negative numbers are treated differently in the filtering operation.
Hans van der Meer
On 29 Apr 2016, at 15:04, Meer, Hans van der
<[email protected]<mailto:[email protected]>> wrote:
Here is a minimal example showing that even a number as -1 is not correctly
handled by the lpath[selection]-code.
I really am convinced that not handling negative numbers should qualify as a
mistake.
Hans van der Meer
% failure of negative number comparison.
\startxmlsetups demo:numberfail
\xmlsetsetup{#1}{root|node}{demo:numberfail:*}
\stopxmlsetups
\xmlregisterdocumentsetup{demo}{demo:numberfail}
\startxmlsetups demo:numberfail:root
@atta >= 1:\crlf
\xmlfilter{#1}{/[number(@atta) >= 1]/command(demo:numberfail:node)}
\blank
@atta >= -1:\crlf
\xmlfilter{#1}{/[number(@atta) >= -1]/command(demo:numberfail:node)}
\xmlfilter{#1}{/[number(@atta) >= number(-1)]/command(demo:numberfail:node)}
\stopxmlsetups
\startxmlsetups demo:numberfail:node
node: attribute atta = \xmlatt{#1}{atta}\crlf
\stopxmlsetups
\startbuffer[numberfail]
<root>
<node atta="2"/>
<node atta="3"/>
</root>
\stopbuffer
\starttext
\xmlprocessbuffer{demo}{numberfail}{}
the error from \type{\xmlfilter{#1}{/[number(@atta) >=
-1]/command(demo:numberfail:node)}}:
\starttyping
xml > lpath > error in expression: number(@atta) >= -1 =>
expr.number((ll.at<http://ll.at/> and ll.at<http://ll.at/>['atta'])) >=
expr.child(ll,'-')1
\stoptyping
the error from \type{\xmlfilter{#1}{/[number(@atta) >=
number(-1)]/command(demo:numberfail:node)}}:
\starttyping
xml > lpath > error in expression: number(@atta) >= number(-1) =>
expr.number((ll.at<http://ll.at/> and ll.at<http://ll.at/>['atta'])) >=
expr.number(expr.child(ll,'-')1)
\stoptyping
\stoptext
___________________________________________________________________________________
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the
Wiki!
maillist : [email protected] / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage : http://www.pragma-ade.nl / http://tex.aanhet.net
archive : http://foundry.supelec.fr/projects/contextrev/
wiki : http://contextgarden.net
___________________________________________________________________________________
