On 28 Apr 2016, at 22:13, Pablo Rodriguez mailto:oinos@gmx.es> wrote: On 04/28/2016 05:06 PM, dr. Hans van der Meer wrote: Why is there anexpression error here? I would expect that the expression number(-10000101) evaluates to a negative number taking part in the comparsion. It looks as if the minus sign is not seen as an unary minus, while -10000101 should have be evaluated by Lua's tonumber(-10000101). relevant code snippet is: \xmlfilter{#1}{lpath[number(@date) <= number(-10000101)]/command(...) I wouldn’t get it, even with a minimal sample, but xml-mkiv.pdf includes the shortcut for this function. 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.athttp://ll.at and ll.athttp://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.athttp://ll.at and ll.athttp://ll.at['atta'])) >= expr.number(expr.child(ll,'-')1) \stoptyping \stoptext

On 5/12/2016 1:49 PM, Meer, Hans van der wrote:

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 tonumber("-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.

it's more that 'names' are intercepted .. can you test (lxml-lpt.lua) with: local lp_child = Cc("expr.child(ll,'") * R("az","AZ") * R("az","AZ","--","__")^0 * Cc("')") Hans

Hans van der Meer

...

On 29 Apr 2016, at 15:04, Meer, Hans van der mailto:H.vanderMeer@uva.nl> 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

...

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