Finding the last element

jeremycod · #1 (**permalink**) March 10th, 2006, 06:54 PM

Hi,
I have the problem with following xml file:

Code:

<chessgame...>
<move> <white>P d2-d4</white>   <black>N g8-f6</black></move>
<move> <white>P c2-c4</white>   <black>P g7-g6</black></move> 
<move> <white>N b1-c3</white>   <black>P d7-d5</black></move>
<move> <white>P c4-d5 x</white> <black>N f6-d5 x</black></move> 
<move> <white>P e2-e4</white>   <black>N d5-c3 x</black></move> 
<move> <white>P b2-c3 x</white> <black>B f8-g7</black></move> 
...

This xml code represent chessgame. The problem is how to find last move for particular figure (note that there is 8 Pawns and all are marked with P). I've trying to solve this problem for a days, but I didn't have to much success. Could anybody suggest me some solution for this problem?
Thanks in advance.

mhkay · #2 (**permalink**) March 10th, 2006, 07:43 PM

First improve the markup to get rid of internal syntax, e.g.

<move>
<ply player="white" piece="P" from="d2" to="d4"/>
<ply player="black".../>

Write a recursive template which walks through all the moves. Pass a parameter which contains the current position of each of the 32 pieces. Update this parameter to reflect the new position of a piece after the move. Copy the move, adding a new attribute that identifies which of the 32 pieces is being moved. (You'll have to do something special for castling, promotion, etc).

Now you've got data that's tagged with the identity of the piece making the move, it's a simple matter of (/game/move/ply)[@piece=$x][last()].

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference

jeremycod · #3 (**permalink**) March 11th, 2006, 12:47 PM

"Pass a parameter which contains the current position of each of the 32 pieces."

How can I pass a parametar with more values? Could you give me some example, please?

joefawcett · #4 (**permalink**) March 11th, 2006, 12:58 PM

You can pass a nodeset as a parameter, not just single values.

--

Joe (Microsoft MVP - XML)

mhkay · #5 (**permalink**) March 12th, 2006, 05:45 PM

You might find it useful to study the "knight's tour" example in my book. This uses most of the techniques needed to solve the problem you described.

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference

Need to download code?

Navigation