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Re: some topics we haven't yet discussed



At 09:13 AM 9/24/96 +0100, Martin Bryan wrote:
>At 07:51 AM 24/9/96 +0100, W. Eliot Kimber wrote:
>
>>>* Should XML change the delimiter-in-context rules to require the STAGO
>>>and ERO strings to be escaped whenever they are not to be recognized as
>>>delimiters (9.6)?
>>
>>This seems like a good idea.  It is easy to use short references to define
>>escape sequences for these, e.g.:  "~<", "~&", "~~" where "~" is the
>>"escape" character (but is really just the first character of a
>>two-character short reference delimiter).  I think a shortref approach is
>>better than MSO, for the reasons given below.  This doesn't break SGML,
>>only requires quoting where it might not otherwise be required (but where
>>people usually do it anyway). 
>>
>>>* Should XML use MSOCHAR, MSSCHAR, and MSICHAR strings (9.7)?
>>
>>No--escaping is easier and safer using shortrefs.
>
>I can't see any difference between defining ~ as a MSSCHAR and defining it
>as an Escape character (given that we have no short references to decode the
>strings shown above, and will therefore rely on application conventions to
>define the escape mechanism). Incidentally, I prefer the tilde to any other
>escape character.

The difference is that MSO and MSI remain as data characters, whereas the
shortrefs simply become the characters, which can be declared as CDATA
entities:

 <!ENTITY srLT    CDATA "<" >
 <!ENTITY srAMP   CDATA "&" >
 <!ENTITY srESC   CDATA "%" >
 <!ENTITY srLSBRK CDATA "[" >
 <!ENTITY srRSBRK CDATA "]" >
 <!ENTITY pseudoS "<pseudo>" > 
 <!ENTITY pseudoE "</pseudo>" >

 <!SHORTREF XMLmap 
       "~<"       srLT
       "~&"       srAMP
       "~~"       srESC
       "~["       srLSBRK
       "~]"       srRSBRK
 >       

Note that this markup is used to process XML as SGML--it isn't need by XML
itself, which simply defines the escape sequences as escape sequences. 

Cheers,

E.
--
W. Eliot Kimber (kimber@passage.com) 
Senior SGML Consultant and HyTime Specialist
Passage Systems, Inc., (512)339-1400
10596 N. Tantau Ave., Cupertino, CA 95014-3535 (408) 366-0300, (408)
366-0320 (fax)
2608 Pinewood Terrace, Austin, TX 78757 (512) 339-1400 (fone/fax)
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