[osis-core] Re: [osis-user] class vs type

[Patrick Durusau]

DM,

I take it is your requirement that you be able to have NMTOKENS as the 
data type for the type attribute?

I don't have any strong objections to space delimited data types so I 
will pass it along to the core group and see if we can get a consensus 
on that.

Our next release will be OSIS 2.5 next Fall. I am hopeful we will see 
some more tools and stylesheets posted in the meantime.

Hope you are having a great day!

Patrick




DM Smith wrote:

>
>
> Patrick Durusau wrote:
>
>> DM,
>>
>> Are you saying that the DTD has a rend attribute that can have 
>> several possible values at the same time?
>
> Yes. Rend is defined as NMTOKENS. Which allows a space separated list 
> of NMTOKEN.
> The global attributes on elements in this system are:
>    id      ID          #IMPLIED
>    lang    IDREF       #IMPLIED
>    n       CDATA       #IMPLIED
>    rend    NMTOKENS    #REQUIRED
>    type    NMTOKEN     #IMPLIED
>
> In some cases rend is not required.
>
> I have mapped
>    this DTD's    OSIS's
>    id            id
>    lang          xml:lang
>    n             n
>    rend          subType
>    type          type
>
>
>>
>> While I don't doubt that is possible, I am not sure why anyone would 
>> want to do it.
>
>
> It does not quite matter why. I am working with a legacy document that 
> has it and I need to preserve it.
> It is needed to express that an element belongs to different classes 
> of presentation simultaneously. See below for more.
>
>>
>> Sounds like a hack to allow poorly written XSLT stylesheets.
>
>
> It has nothing to do with XSLT stylesheets. Its for CSS stylesheets. 
> XSL was originally intended to allow the transformation and the 
> styling of a document. XSLT only implemented the transformation 
> aspect. IIRC, it was felt that CSS would do the job of presentation. I 
> haven't looked at it yet but it looks like xsl-fo is intended to style 
> a document.
>
> The value of the HTML class attribute and this DTD's rend attribute is 
> that it allows for the separation of presentation and content. Prior 
> to it, one embedded the presentation directly into the document.
>
>>
>> For example, if I have <q type = "emphasis">, even though I only have 
>> one value for type, nothing prevents me from having different 
>> renderings of the contents of <hi> based upon its position in the 
>> markup tree, for example <hi type="emphasis"> being rendered 
>> differently when it is a child of <title> from when it is a child of 
>> <p> versus when it is a child of <q>.
>
>
> This is absolutely true and has no bearing on whether rend has one 
> value or multiple ones. Or whether having multiple value is of any 
> value (pun intended).
>
> Allowing multiple values allows the expression of different kinds of 
> roles/dimensions to be used at the same time.
>
> For example, we may want an ordered list or an unordered list. And 
> because nesting is allowed, we may have lists of lists. And any list 
> in the tree can be either. But what if we want to have different kinds 
> of ordered lists and unordered lists.
> Say
>    revealed - all the children of a node are shown with the parent
>    initially-hidden- all the children of a node are initially hidden 
> but stay shown until hidden again
>    popup - shown for a time when a user expresses interest in them.
> And, as an processing optimization it is needed to be known whether 
> the list of children is to not wrap, wrap in a narrow presentation or 
> a wide presentation.
>
> And in this example, it is both possible and reasonable to have a list 
> of children that have different behaviors.
> (This is a simplification of real world example of a system I wrote 
> using CSS. There were other dimensions as well, such as data source: 
> synthetic, program generated, user input. The HTML document were 
> simple lists with <ul> and <ol> having multiple class values, with 
> each class value representing a different concept.)
>
> To do this with a single value, I would need one for each possible 
> combination; in this case a set of 2x3x3=18 different values. (Well 
> actually 9, because HTML has ul and ol)
>
> In the case at hand, the element is a paragraph tag. It is not clear 
> what the different values are, but let me suppose that they deal with 
> justification, first-line indentation, subsequent-line indentation, 
> line spacing, handling of first letter, etc. The application of these 
> behaviors is entirely unpredictable in the document, so creating a 
> general purpose stylesheet is out of the question and a specific one 
> would end up as a complex program that has too great a knowledge of 
> the document.
>
> Since I am dealing with transforming a legacy document into OSIS, I 
> need a way to preserve the values. I am wondering how. (As a 
> programmer, I can figure out many work arounds, such as littering the 
> document with hi elements or replacing spaces with a character that is 
> not allowed in NMTOKEN, like ':' type="x-multivalue:a:b:c") And if 
> this ability will be added to a later version of osis, I would like to 
> pick a hack that would allow a good path to it tomorrow.
>
> In order to separate presentation from structured content, there needs 
> to be a semantic for deterministically attaching presentation to 
> content. This is what the class and rend attribute provide.
>
>>
>> Does that catch the gist of the problem or have I misunderstood the 
>> issue? (It is 5 AM local time so the latter is entirely possible.)
>>
>> Hope you are having a great day!
>
> And I hope you are having a good and full night of sleep.
>
> --DM
>
>>
>> Patrick
>>
>>
>> DM Smith wrote:
>>
>>> In html elements define a class attribute which indicates that a 
>>> particular element in its context belongs to a class of that 
>>> element. The primary use of this is to indicate where styles can be 
>>> attached. It appears that type can be used for the same purpose, but 
>>> not quite. In html, class is defined as "class    space separated 
>>> list of classes" It's type is CDATA, but in spirit is NMTOKEN. What 
>>> this allows is for an element to be cross-classified. That is more 
>>> than one class can apply.
>>>
>>> However in OSIS there is only one type "word" that can be used.
>>>
>>> I am working to convert an xml document to OSIS. This document's DTD 
>>> defines an attribute, rend, in much the same way as class, in that 
>>> it is a "role" to which style should be applied, with the 
>>> possibility of several "roles".
>>>
>>> What is the proper way to do this?
>>>
>>> I can figure out several ways to do this but none seem quite right. 
>>> For example, artificially, I can nest <hi> elements to achieve a 
>>> similar, but not quite the same result.
>>>
>>>
>>>
>>
>
>
>

-- 
Patrick Durusau
Patrick at Durusau.net
Chair, V1 - Text Processing: Office and Publishing Systems Interface
Co-Editor, ISO 13250, Topic Maps -- Reference Model
Member, Text Encoding Initiative Board of Directors, 2003-2005

Topic Maps: Human, not artificial, intelligence at work!