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RE: [xsl] What is a good way to style and show tabular data [snip]
Subject: RE: [xsl] What is a good way to style and show tabular data [snip] From: "SANWAL, ABHISHEK (HP-Houston)" <abhishek.sanwal@xxxxxx> Date: Tue, 19 Aug 2003 14:39:18 -0500 |
To: XSL-List Cc: Wendell Cc: Peter I am wondering if you could give me some suggestions on the actual XML at hand. In this matrix/table design I am only thinking for 2-D Data & Layout. Of course that is the medium I can write to now and that is the content. I am trying to eliminate the notion of absolute vertical or horizontal flow styling for the table thereby allowing me to lay the table out with the head on the top or the head on the left ( maybe even the right ?? ). I am inserting sample XML and a partially done XSL where I would like some suggestions on how I could improve the XML and the XSL to make them do the "Vertical" flow that I have not yet completed. (V - Vertical, H - Horizontal) <Matrix HeadFlow="V|H" HeadExists="1" HeadCount="4" DataCount="1"> <MatrixHeadArray> <MatrixHeadCell i="1">Standard 1</MatrixHeadCell> <MatrixHeadCell i="2">Maximum 2</MatrixHeadCell> <MatrixHeadCell i="3">Standard 3</MatrixHeadCell> <MatrixHeadCell i="4">Maximum 4</MatrixHeadCell> </MatrixHeadArray> <MatrixDataArray j="1"> <MatrixDataCell i="1" j="1">1024 MB </MatrixDataCell> <MatrixDataCell i="2" j="1">32GB</MatrixDataCell> <MatrixDataCell i="3" j="1">512 MB </MatrixDataCell> <MatrixDataCell i="4" j="1">32GB</MatrixDataCell> </MatrixDataArray> </Matrix> I have been able to create an HTML Table output stylesheet for a Horizontal Head Flow as shown below ( I am using a xsl:choose to apply the different ones). I would like to know what would be a good and/efficient way to WRITE the code for the VERTICAL head flow. (Any ideas appreciated, snippets of code... well will be worshipped .. hehe ) <xsl:choose> <!-- For Horizontal Head Flow Tables --> <xsl:when test="@HeadFlow[.='Horizontal']"> <h2>Horizontal</h2> <!-- Just for the sake of visibility --> <tr> <xsl:for-each select=".//MatrixHeadCell"> <th> <xsl:value-of select="."/> </th> </xsl:for-each> </tr> <xsl:for-each select=".//MatrixDataArray"> <tr> <xsl:for-each select=".//MatrixDataCell"> <td> <xsl:value-of select="."/> </td> </xsl:for-each> </tr> </xsl:for-each> </xsl:when> <!-- For Vertical Head Flow Tables --> <xsl:when test="@HeadFlow[.='Vertical']"> <h2>Vertical</h2> <!-- Just for the sake of visibility --> <!-- THIS NEEDS TO BE WRITTEN --> </xsl:when> <xsl:otherwise> <p>No Flow for Matrix Defined Hence cannot be rendered</p> </xsl:otherwise> </xsl:choose> Abhishek Sanwal HP - Houston Campus abhishek.sanwal@xxxxxx (O): +1-281-518-4707 (M): +1-469-569-4605 ------------------------------------------------------------------------ ---- Abhishek, Your line of thought is interesting, because you are treading into the midst of an area where the common XML dogma "separation of format from content" breaks down.... Peter made the classic argument for semantically-meaningful names, etc. (with which I entirely agree), but your counter example shows that the whole issue of "tabular data" is just the tip of a very large, deep iceberg, which threatens to split our ocean liner in two, half tending towards modeling our content semantically -- because we know that's a Good Idea -- robust, scalable, long-lived, versatile etc. etc. --, half towards giving up and modeling for presentation -- because a generalized semantic model proves to be very difficult, whereas just modeling a two-dimensional rows and columns is a clear way forward to our immediate goal. Why does a generalized semantic model prove to be difficult? One reason is that XML's "natural" tree structure is not capable, without enhancement, of modeling the n-dimensional matrices which often prove to underlie tabular renditions. (And yes, folks, look at printed materials of any complexity and you will not uncommonly find 3-, 4- or more-dimensional matrices presented as tables.) In view of these challenges, you might consider how the classic solution -- for example, the OASIS (CALS) table (which Peter mentions) -- goes about it. Model a conventional rows-and-columns (2-dimensional) table; annotate cells with attributes to identify their roles and semantic relations. This is kind of a split-the-difference solution, which "solves" the problem for presentation, but not necessarily or entirely for generalized processing. This is because semantic relations of critical importance to the integrity of the data set are pushed out into the attribute names and values, thereby requiring special kinds of checks, validation etc. to keep everything together. The other approach is to forget completely how something is to be presented, and simply (heh) model everything to its own proper semantics. In the domain of publishing, for which XML was (at least partly) designed for, this is often prohibitively difficult, since each table has its own semantics (prices for parts by quantities here, over there populations by region and age group, etc. etc.), and this threatens indefinite extension to the tag set. If however, you are working in a problem space where such data structures are regular and predictable, this is the preferred solution. Model it for what it is (a set of name-value pairs, an object hierarchy, whatever), and worry about how to display it later. As for the generalized n-dimensional solution, supporting querying, transposition etc. to get the tabular "views" -- that's still an interesting area for research. Cheers, Wendell >I initially had a <td>, <th> kind of structure but I realized that it >was locked to have a head that flowed horizontally only so I added the >idea of a matrix that could flow in V or H directions and could be >transposed at will. Of course in this structure if there is a "sparse" >matrix (one with very few "filled" cells) then I will have to have a >large number of "empty" cell holders for positioning things properly. > >The other way to "enrich" the data would be to add attributes of "i and >j" to define positions of the cells so that position information is not >dependent on the "actual" placement in the XML. At 10:57 AM 8/18/2003, you wrote: >Peter, > >I totally agree with you. I truly believe it would be better to have >"rich" and "well defined" markup than to try and go crazy in the >stylesheet. > >I identify with the "list" example you mentioned and have done a >similar thing. But that is when the "cells or data holders" were simply >associative in ONLY "one" direction. > >When there is "cell associativity" in 2 Dimensions (or directions) it >needs to be in a table form (more precisely it needs to be in a >2Dimensional Matrix). > >But I have realized that there is a trade-off when trying to add markup >to the XML to make XSLs easier. So, I have tried to keep certain >aspects of the markup "open". For example, the list is a good way of >eliminating an unnecessary "2 column table". > >Now, to the specifics: > >This is how I have currently modeled the XML for the table/matrix. > ><Matrix HeadFlow="Vertical | Horizontal"> > <!-- (optional) --> > <MatrixHeadArray> > <MatrixHeadCell>a</MatrixHeadCell> > <MatrixHeadCell>b</MatrixHeadCell> > <MatrixHeadCell>c</MatrixHeadCell> > </MatrixHeadArray> > <MatrixBodyArray> > <MatrixBodyCell>d</MatrixBodyCell> > <MatrixBodyCell>e</MatrixBodyCell> > <MatrixBodyCell>f</MatrixBodyCell> > </MatrixBodyArray> ></Matrix> > >I initially had a <td>, <th> kind of structure but I realized that it >was locked to have a head that flowed horizontally only so I added the >idea of a matrix that could flow in V or H directions and could be >transposed at will. Of course in this structure if there is a "sparse" >matrix (one with very few "filled" cells) then I will have to have a >large number of "empty" cell holders for positioning things properly. > >The other way to "enrich" the data would be to add attributes of "i and >j" to define positions of the cells so that position information is not >dependent on the "actual" placement in the XML. > >So I am thinking what would be a good way to go about this. Please do >let me know. > >Thanks, > >Abhishek Sanwal >HP - Houston Campus >abhishek.sanwal@xxxxxx > > >-----Original Message----- >From: Peter Flynn [mailto:peter@xxxxxxxxxxx] >Sent: Sunday, August 17, 2003 4:23 PM >To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx >Subject: Re: [xsl] What is a good way to style and show tabular data >[snip] > >On Fri, 2003-08-15 at 23:41, SANWAL, ABHISHEK (HP-Houston) wrote: > > What is a good way to style and show tabular data > >In a table, usually. > > > and what is a good way to store Tabular data in XML > >There is only one "good" way to store data in XML -- any data -- and >that is in a well-designed structure which preserves as much >information about the data as is needed for you to work with it >successfully. Storing data (or text) in a suboptimal structure, with >misleading names, poor content models, ambiguous attributes, failing to >take advantage of some of >the obvious features of XML, perpetrating Tag Abuse, creating Pernicious >Mixed Content, and all the other nasties in the corner; and in a manner >which loses some metadata as the data is stored, is a recipe for tears >and >grief, as we see daily here and elsewhere :-) > >Get the data model right first, and the rest will follow. >Get the data model wrong, and you will spend excessive time having to >undo it or cope with it while it remains wrong. > >But in a production situation this is not always possible: data from >elsewhere in a silly format, management insisting white is black when >you know it's actually green, client or vendor insistence on >unsuitable, often >proprietary, formats for political reasons, etc. > >For tabular data, there are many solutions, and without seeing an >example any advice has to be general. My personal preference is to use >meaningful >names (ie not TR, TD, and TH :-) and to ensure that sufficient metadata >is stored to enable the original structure to be recreated (the "round >trip" >test). But in the pressure to get stuff done, you may choose to do >otherwise. > >But there is one classical case where data is often stored as a table >quite wrongly: the labelled list. Consider: > > USA You pay insurance for healthcare, only people > below a (very low) income level get state-funded care > > UK You get healthcare free at the point of usage in > most cases, paid for via income deductions, but > insurance-funded ("private") healthcare is available > >(Forgive me USA and UK if I have the facts wrong :-). To most >wordprocessor users this looks like a table, because it's the only way >their wordprocessor has of formatting it. But it's not a table: it's a >list whose format resembles a columnar layout. Storing it as a list in >XML lets you choose how to format it for output very easily. Storing it >as a table risks making it uneditable and unformattable except with >much greater difficulty. > > > especially when the only purpose for that data is to be styled by > > stylesheets into XSL-FO (PDF) and HTML - such that the stylesheets > > are efficient, extensible and not too cumbersome. > >There are three common table models: CALS, SASOUT, and HTML (see >Chapter 2, section 3.7 of my book on SGML and XML Tools for a detailed >description). Another one, ISO/IEC TR 9573 I have lost track of -- >maybe it still exists. CALS is huge, but lets you store all kinds of >fine detail about layout and appearance; SASOUT tries to let you define >the relationships between rows, columns, and cells, but I don't think >it ever really caught on; HTML is simplistic to the point of crudity, >but better supported in browsers than anything else (but harder to use >for good quality print). > >The better the quality of XML markup, the easier it is to work with. If >your markup allows you to record what the data is, and why it is stored >in this way, it's usually much easier to write a stylesheet to format >it than having to spend large amounts of time coding large nests of >conditionals to try and deduce aspects of the nature of the data which >ought to have been stored explicitly. But as I said, this is the ideal: >in practice most people stuff it into TR, TD, and TH and hope for the >best. > >///Peter > > > > > XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list > > > XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list ====================================================================== Wendell Piez mailto:wapiez@xxxxxxxxxxxxxxxx Mulberry Technologies, Inc. http://www.mulberrytech.com 17 West Jefferson Street Direct Phone: 301/315-9635 Suite 207 Phone: 301/315-9631 Rockville, MD 20850 Fax: 301/315-8285 ---------------------------------------------------------------------- Mulberry Technologies: A Consultancy Specializing in SGML and XML ====================================================================== XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list
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