- From: Gregg Vanderheiden <po@trace.wisc.edu>
- Date: Thu, 2 Oct 1997 08:55:46 -0500
- To: "'Al Gilman'" <asgilman@access.digex.net>, "'HC team'" <w3c-wai-hc@w3.org>
Woa This is good stuff but.. How much of this can be either - be done automatically (no author intervention needed) - or bbe done by the author by making a simple gesture or dealing with it in very simple english terms. I am concerned that people laying out tables will do it WYSIWYG and won't even know what a spanning title is (even if they use one) much less be able to tell the program whether the table is row or column dominant. Can you help me by saying what this would look like to an author? What would they be asked to tell the web author tool about the table in order to get the tool to code the table html correctly? (assuming the best case with regard to html being able to code the info) Gregg -----Original Message----- From: Al Gilman [SMTP:asgilman@access.digex.net] Sent: Wednesday, October 01, 1997 1:12 PM To: HC team Subject: more on TABLEs to follow up on what T. V. Raman said: > Subject: operational concept for table browsing > > > Good start-- I'll add things in to your original message below: Edits accepted as friendly amendment. Let's make Raman's edit our baseline as of now. > In addition, many tables are not meaningful unless the user > has the ability to produce customized renderings where these > minimally include speaking a cell with its row/column headers > and in the ideal world include renderings of the form > "Total population growth in %s was %s " cell (i,2) , cell (i,1) Dave and I have kicked around investigating what the requirements are for a readout script that generates this verbalization of the meaning of a cell's value. At last mention it was considered worth working on some more. It may be deemed a styling statement in the end but it dominates my thinking on how to capture core semantics. My thinking revolves around defining self.attribute variable names or relationship names that one would cite in such a script in lieu of the cell (i,2) , cell (i,1) coordinate-wise references above. Maybe we should look at relative position coordinates as an alternatives to what I am doing which is attribute names in an information model. But to continue on the logical-relationship-name path for a moment, I want to distinguish two kinds of relationships from the current [TD | TH] cell to other [TD | TH] cells. For each kind of relationship, there is a variable and an attribute that are related but not identical. Consider A variable self.is_a which is a tree of cells. A cell attribute IS-A= which is a set of TH cells. The value of the variable is the tree of one [TH or TD] cell "self" as root and multiple TH cells which are directly or indirectly the targets of is-a relationships from the starting cell. Is-a relationships can be created explicity by attribute assertions in [TD | TH] cells or implicity by rules based on information asserted at the row, column, or table level. The TH cells in the self.is-a tree define how to interpret the value in the cell. Example: in the expense account table that Dave put together, the self.is-a for all cells in rows 2 and up and columns B and up is [the current TD cell linked to a TH cell at (row=1,col=A)] For clarity please imagine this upper-left TH cell contains the text "actual cost in US$." Here the simplest way to capture the global effectivity of this TH is to have an effectivity indictation such as DOMAIN="2,,B," marked in the TH cell. Note: If I have it right, both the AXIS and AXES attributes defined in the current draft are special cases of IS-A. Then I want to define A variable self.keys which is a set of [TD | TH] cells A cell attribute KEYS= which is likewise a set of [TD | TH] cells In this case, continued relationships are illegal. A given cell can be the source or target of a keys relationship, but not both. Sources of "keys" relationships are interpreted as dependent variables. Targets of "keys" relationships are interpreted as independent variables. But the value of the self.keys variable is not limited to what is explicitly asserted in a KEYS= attribute indication in the cell. One possible shorthand form for establishing keys is that columns may be designated key in which case the values in that column are keys for all non-key values in the same row. The keys completely define the conditions under which the cell value is valid. To return to the Travel Expense Report example, for the subtotal of expenses for meals in San Jose which is the content of cell (5,B) we have (5.B).keys={(2,A),(1,B)}. In this table there are keys to the left and above and qualifiers only at the table-global level. This brings us to the next suggestion: CLASSES of TABLES. Greg Lowney has suggested row-major, column-major, and "both," as I recall. I want to try out an alternative explanation in terms of which grouping within the table has the strongest cell wall or bonding strength. Thus there are four cases: rows, columns, whole, or cell. Think about what the default rules would be for populating self.is-a and self.keys under each of these four cases. Note that I think Dave's expense report gets classified as having strongest bonding at the whole table level. And that "layout tables" get classified as having strongest bonding at the cell level. Note that if it is just a matter of driving browser-specific presentation algorithms, we can handle this by CLASS indications on the TABLE element and the HTML document is untouched; on the other hand, to predefine the cell-context variables I discussed above on a class-by-class basis, we have to at least predefine some CLASS values, or else define an attribute to capture this distinction. -- Al
Received on Thursday, 2 October 1997 09:58:22 UTC