[XeTeX] Whitespace in input

[Ross Moore]

Hello Zdenek,

On 18/11/2011, at 7:49 AM, Zdenek Wagner wrote:

>> But a formatting instruction for one program cannot serve as reliable input
>> for another.
>> A heuristic is then needed, to attempt to infer that a programming
>> instruction must have been used, and guess what kind of instruction it might
>> have been. This is not 100% reliable, so is deprecated in modern methods of
>> data storage and document formats.
>> XML based formats use tagging, rather that programming instructions. This is
>> the modern way, which is used extensively for communicating data between
>> different software systems.
>> 
> Yes, that's the point. The goal of TeX is nice typographical
> appearance. The goal of XML is easy data exchange. If I want to send
> structured data, I send XML, not PDF.

These days people want both.

> 
>> ** Phil.
>> 
>> TeX's strength is in its superior ability to position characters on the page
>> for maximum visual effect. This is done by producing detailed programming
>> instructions within the content stream of the PDF output. However, this is
>> not enough to meet the needs of formats such as EPUB, non-visual reading
>> software, archival formats, searchability, and other needs.
>> Tagged PDF can be viewed as Adobe's response to address these requirements
>> as an extension of the visual aspects of the PDF format. It is a direction
>> in which TeX can (and surely must) move, to stay relevant within the
>> publishing industry of the future.
>> 
>> Hope this helps,
>>     Ross
>> 
> No, it does not help. Remember that tha last (almost) portable version
> of PDF is 1.2. If you are to open tagged PDF or even PDF with a
> toUnicode map or a colorspace other than RGB or CMYK in Acrobat Reader
> 3, it displays a fatal error and dies. I reported it to Adobe in March
> 2001 and they did nothing.

What else would you expect?
AR is at version 10 now.
On Linux it is at version 9 now, indeed 9.4.6 is current.

You don't expect TeX formats prior to TeX3 to handle non-ascii 
characters, so why would you expect other people's older software 
versions to handle documents written for later formats?

> I even reported another fatal bug in
> January 2001. I sent sample files but nothing happened, Adobe just
> stopped development of Acrobat Reader at buggy version 3 for some
> operating systems.

Why should they support OSs that have a limited life-time?
Industry moves on. A new computer is very cheap these days,
with software that can do things your older one never could do.

By all means keep the old one while it still does useful work, 
but you get another to do things that the older cannot handle.

> Why do you so much rely on Adobe? When exchanging
> structured documents I will always do it in XML and never create
> tagged PDF because ...

PDF, as a published standard, is not maintained by Adobe itself 
these days, yet Adobe continues to provide a free reader, at least 
for the visual aspects. That makes documents in PDF viewable by 
everyone (who is only interested in the visual aspect).

It is an ISO standard, which publishers will want to use.
Most of the people who use (La)TeX are academics or others
who need to do a fair amount of publishing, of one kind
or another.

TeX can be modified to become capable of producing Tagged PDF.
     (See the videos of my talks.)
Free software (Poppler) is being developed to handle most aspects
of PDF content, though it hasn't yet progressed enough to support
structure tagging. It's surely on the list of things to do.

>  ... I know that some users will be unable to read them
> by Adobe Acrobat Reader.

Why not?
It is not Adobe Reader that is holding them back.

> I do not wish to make them dependent on
> ghostscript and similar tools.

You'll have to give some more details of who you are
referring to her, and why their economic circumstances 
require them to have access to XML-transmitted data,
but preclude them from access to other kinds of standard 
computing software and devices.


> -- 
> Zdeněk Wagner
> http://hroch486.icpf.cas.cz/wagner/
> http://icebearsoft.euweb.cz


Hope this helps,

	Ross

------------------------------------------------------------------------
Ross Moore                                       ross.moore at mq.edu.au 
Mathematics Department                           office: E7A-419      
Macquarie University                             tel: +61 (0)2 9850 8955
Sydney, Australia  2109                          fax: +61 (0)2 9850 8114
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