* xml expression error
@ 2016-04-28 15:06 dr. Hans van der Meer
2016-04-28 20:13 ` Pablo Rodriguez
0 siblings, 1 reply; 6+ messages in thread
From: dr. Hans van der Meer @ 2016-04-28 15:06 UTC (permalink / raw)
To: NTG ConTeXt
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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(...)
xml > lpath > error in expression: number(@date) <= number(-10000101) => expr.number((ll.at and ll.at['date'])) <= expr.number(expr.child(ll,'-')10000101)
Changing number(-10000101) to -10000101 does not make a difference.
The @date attribute has no problem with a negative value.
Hans van der Meer
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: xml expression error
2016-04-28 15:06 xml expression error dr. Hans van der Meer
@ 2016-04-28 20:13 ` Pablo Rodriguez
2016-04-28 21:12 ` Meer, Hans van der
2016-04-29 13:04 ` Meer, Hans van der
0 siblings, 2 replies; 6+ messages in thread
From: Pablo Rodriguez @ 2016-04-28 20:13 UTC (permalink / raw)
To: mailing list for ConTeXt users
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(...)
Sorry, Hans, I guess my question will be stupid, but why don’t use
"tonumber(-10000101)"?
I wouldn’t get it, even with a minimal sample, but xml-mkiv.pdf includes
the shortcut for this function.
Just in case it might even help ;-),
Pablo
--
http://www.ousia.tk
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: xml expression error
2016-04-28 20:13 ` Pablo Rodriguez
@ 2016-04-28 21:12 ` Meer, Hans van der
2016-04-29 13:04 ` Meer, Hans van der
1 sibling, 0 replies; 6+ messages in thread
From: Meer, Hans van der @ 2016-04-28 21:12 UTC (permalink / raw)
To: NTG ConTeXt
> On 28 Apr 2016, at 22:13, Pablo Rodriguez <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(...)
>
> Sorry, Hans, I guess my question will be stupid, but why don’t use
> "tonumber(-10000101)"?
It is convenient to use positive numbers for dates after the year 0: AD = Anno Domine,
and negative numbers for years before: BC = Before Christ.
Comparing dates is easy in both eras.
>
> I wouldn’t get it, even with a minimal sample, but xml-mkiv.pdf includes
> the shortcut for this function.
>
> Just in case it might even help ;-),
Has to wait until tomorrow, because it is already late in the evening.
Hans van der Meer
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: xml expression error
2016-04-28 20:13 ` Pablo Rodriguez
2016-04-28 21:12 ` Meer, Hans van der
@ 2016-04-29 13:04 ` Meer, Hans van der
2016-05-12 11:49 ` Meer, Hans van der
1 sibling, 1 reply; 6+ messages in thread
From: Meer, Hans van der @ 2016-04-29 13:04 UTC (permalink / raw)
To: NTG ConTeXt
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On 28 Apr 2016, at 22:13, Pablo Rodriguez <oinos@gmx.es<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.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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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: xml expression error
2016-04-29 13:04 ` Meer, Hans van der
@ 2016-05-12 11:49 ` Meer, Hans van der
2016-05-12 22:10 ` Hans Hagen
0 siblings, 1 reply; 6+ messages in thread
From: Meer, Hans van der @ 2016-05-12 11:49 UTC (permalink / raw)
To: NTG ConTeXt
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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 <H.vanderMeer@uva.nl<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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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: xml expression error
2016-05-12 11:49 ` Meer, Hans van der
@ 2016-05-12 22:10 ` Hans Hagen
0 siblings, 0 replies; 6+ messages in thread
From: Hans Hagen @ 2016-05-12 22:10 UTC (permalink / raw)
To: mailing list for ConTeXt users
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 <H.vanderMeer@uva.nl
>> <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
>
>> ___________________________________________________________________________________
>
>
>
> ___________________________________________________________________________________
> If your question is of interest to others as well, please add an entry to the Wiki!
>
> maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
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> wiki : http://contextgarden.net
> ___________________________________________________________________________________
>
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2016-04-28 15:06 xml expression error dr. Hans van der Meer
2016-04-28 20:13 ` Pablo Rodriguez
2016-04-28 21:12 ` Meer, Hans van der
2016-04-29 13:04 ` Meer, Hans van der
2016-05-12 11:49 ` Meer, Hans van der
2016-05-12 22:10 ` Hans Hagen
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