[xml] XPATH Numbers don't work

[Uwe Fechner <ufechner 4commerce de>]

Hello,

I am using libxml2.dll version 2.4.10 for windows. (from Igor).
I use the delphi-header-translations from
http://sourceforge.net/projects/libxml2-pas.
(Together with delphi 6.0 fixpack 1).

I have a problem using xpath.

The results are ok if they have the type nodeset.

Results of type number are always zero, strings are always empty.

Here my code:

Procedure test3(filename, expr: string);
// An Example Programm for the use of XPATH-expressions
// (without the xmldom.pas interface)
var doc: xmlDocPtr;
    node: xmlNodePtr;
    ctxt: xmlXPathContextPtr;
    res:  xmlXPathObjectPtr;
    temp: string;
    type_: integer;
    number: double;
begin
  // read the input file
  filename:='..\data\'+filename;
  StartTimer;
  doc:=xmlParseFile(pchar(filename));
  if doc<>nil then begin
    outLog('Parsed file ok!');
    outLog('Elapsed time: '+format('%8.1f',[EndTime*1000])+' ms');
  end
  else exit;
  node:=xmlDocGetRootElement(doc);
  if node=nil then exit;
  // xpath
  ctxt:=xmlXPathNewContext(doc);
  ctxt.node:=node;
  res:=xmlXPathEvalExpression(pchar(expr),ctxt);
  //res:=xmlXPathEval(pchar(expr),ctxt);
  if res=nil then exit;
  type_:=res.type_;
  case type_ of
    XPATH_UNDEFINED:
      begin
        temp:='Undefined';
      end;
    XPATH_NODESET:
      begin
        temp:='Nodeset of '+inttostr(res.nodesetval.nodeNr)+' nodes';
      end;
    XPATH_BOOLEAN:
      begin
        if res.boolval=0
          then temp:='Boolean: false'
          else temp:='Boolean: true';
      end;
    XPATH_NUMBER:
      begin
        number:=res.floatval;
        temp:='Number: '+floattostr(number);
      end;
    XPATH_STRING:
      begin
        temp:='String: '+res.stringval;
      end;
    else
      begin
        temp:='???';
      end;
  end;
  outLog(temp);
  xmlXPathFreeObject(res);
  xmlXPathFreeContext(ctxt);
end;

If I test:

> filename:='calServer.xml';
> expr:='round(3)';
> test3(filename,expr);

the output is:

> Parsed file ok!
> Elapsed time:     30,5 ms
> Number: 0


If I test:

> filename:='calServer.xml';
> expr:='concat("uwe","fechner")';
> test3(filename,expr);

the output is:

Parsed file ok!
Elapsed time:     16,5 ms
String:

Any idea?

Best regards:

Uwe Fechner