- From: Al Gilman <asgilman@iamdigex.net>
- Date: Fri, 20 Oct 2000 20:36:11 -0400
- To: "UA List (E-mail)" <w3c-wai-ua@w3.org>
1. Why is this conversation happening now? Are we making changes like this to the PR draft? 2. There is no need for a Term of Art, here, because the sense of 'element' in the WCAG provisions that are the basis for the UAAG provisions in question is a natural English sense of "a constituent part" [c.f. <<http://www.m-w.com/cgi-bin/dictionary>http://www.m-w.com/cgi-bin/dictionar y>, search on 'element,' select sense #2]. That said, Let me clear up the usage in this area just a bit. There is rampant in the community an ambiguity in the use of 'element' between denoting an actual part of an actual document [instance] vs. an element type specified (in a DTD or otherwise) for use in markup to delimit and classify the previous, more concrete sort of 'element.' To make the distinction clear, one could use 'element' and 'element type' but often 'element' gets reassigned and we wind up talking about 'element instance' and 'element.' Under the circustances there is no reader-safe usage except to say 'element instance' when one means a specific part of a specific document, and 'element type' when one specifically means a category of the above, such as for example all the element types defined in HTML, the dialect of SGML. However: the sense of 'element' in the WCAG 1.0 discussion of "text equivalents for non-text elements" is the natural English sense of "a constituent part" and not the syntax-technical sense of "an instance of a markup construct defined as an element in the formal specification of the markup dialect." The fact that it is not the technical sense may bear mentioning, but this is a warning, not a 'definition.' Note: The phrase 'logical construct' is much too broad as it includes categories such as 'connective' or 'preposition' or 'reference' which are never referred to as 'elements' in the disucssions in the WAI documents. The category of 'logical constructs' that we use 'element' for is 'element types.' There is no need to fall back any further into looser categories. Warning 1: It is important to understand the design elements of a web page as including the actual image embedded in the document by an IMG element in the markup language, although regarding the document as just the HTML text of the source one would find that only a reference to the image is preseant in the IMG element in the HTML file. Warning 2: It is perfectly legitimate, however, for someone to talk about header font and type color scheme as elements of a company's branding scheme. This is a pattern of properties that is not a document part and it is not represented by an XML or SGML element type definition in the formal organization of the markup language. But it can be said in one of our documents without breaking our usage because it is just another example of the plain English sense of 'element.' The key is that it is made clear in the context what this syndrome of presentation properties is an element (i.e. part of component) _of_. There was question as to whether 'element' refers to a type of content. Not quite. The point is that all the named elements in HTML and other SGML and XML applications _do_ have connotations as to categories that the content range so marked falls within. But these categories are often heuristic, that is to say not machine-interpretable without the aid of a natural-language-capable human. So although one of the common senses of 'element' is 'element type,' and 'element type' does contain information about what kind of stuff is in there, an 'element type' is not a kind of stuff, but rather a kind of part which has restrictions as to the kind of stuff one will find in it (and its role in the context). Webster lists "a constituent part" as the second sense of 'element' and that is the generic sense used throughout UAAG and the rest of the WAI literature. It is inadvisable to try to give a reserved meaning to 'element' in the UAAG as a whole. If you want to make the usage more precise in various places, it could be useful to introduce glossary entries for "element instance" and "element type" and place a note in the glossary indicating that 'element' has been used for either of these or the Webster sense "a constituent part" interchangeable where it is clear from the context which of these is intended. We should endeavor, and say we have so tried, to use "element instance" or respectively "element type" where the distinction is important. Note: there is no need to be concerned about how 'element' is defined as used in the glossary entry for "text element." The introduction of "text element" in the glossary is gratuitous. Searching for this phrase encounters no hits until it appears in the glossary. It is a self-requiring exercise in unnecessary definition of terms. However, if you wish to understand what "text element" and "non-text element" should mean in the satisfaction of WCAG, please consider the following nominations: * A _text element_ is a constituent part of the document (i.e. in the general, not syntax-technical sense) whose content is entirely composed of text and properties of that text. * A _non-text element_ is a constituent part of the document (same proviso) that is not a text element and cannot be reasonably decomposed into constituent parts some of which are text elements and some are not. The main reason for putting a glossary entry in the document is that readers of the content may be markup-language-literate and will need to be warned that the syntax-technical sense is not what is intended [in the WCAG language]. Note that since the issue here is echoing the WCAG requirement, the appropriate way to get usage clarification would be to ask the WCA WG for an interpretation of the document. All of this is dependent of understanding that 'part' in the above indicates something which contains a subset of the content of the document, _and_ would be recognizable by a reasonable user as a thing in its own right. Al At 05:15 PM 2000-10-20 -0400, Hansen, Eric wrote: >I wanted to make sure that our definition of "Element" adequately covers our >usage in definitions such as "Text element". Is our usage as a "logical >construct" or something else? I think it as a "unit of content" rather than >necessarily being tied to particular "type of content". For example, a >"multimedia presentation" might be considered an element, but also might its >visual track or even a text equivalent of a visual track might be considered >"elements". > >Your comments welcome. > >Old (29 September 2000): > >"Element This document uses the term "element" both in the XML sense (an >element is a syntactic construct as described in the XML 1.0 specification >[XML], section 3) and more generally to mean a type of content (such as >video or sound) or a logical construct (such as a header or list)." > >New: > >"Element This document uses the term "element" both in the XML sense (an >element is a syntactic construct as described in the XML 1.0 specification >[XML], section 3) and more generally to mean a unit of content (text element >or non-text element) or a logical construct (such as a header or list)." > ><END OF MEMO> >
Received on Friday, 20 October 2000 20:10:47 UTC