[SML] Comments ( Whether to support Attribute or not? )

Paul Tchistopolskii paul at qub.com
Sat Nov 27 09:37:40 GMT 1999


From: Rick Jelliffe <ricko at allette.com.au>

> From: Don Park <donpark at docuverse.com> 
> 
> >I believe it is now time to address the question of
> >whether Attribute should be supported in SML or not.
>  
> Because it is convenient for programming. 

I think it is not. 

It may be convinent for writing the document, but it 
introduces especial syntax for *processing* the 
document.

It's similiar to ... If we require in, say, C++  to use 

a   = B;        // B is variable
a $= B;        // B is constant

> It seems that most XML programs are written so that
> the elements "push" programs but attributes values
> are "pulled" in.  So the programmer does not need
> to concern themselves with attributes that are redundant
> to their task.  To make everything an element would 
> reduce the choices available to a programmer.

I don't understand. I simply don't understand. 

Well ...  maybe you are saying  that removing the kludge 
from a $= B redices some choices ... Maybe it does. 
It's the issue of taste, I think. 

However, it's very common thing when something 
designed to be a constant  becomes a variable 
( and back ). I already experienced the same 
things with attributes and elements.
 
> Are you talking about syntax or labelling here?  You can
> see that some people say "lets remove attributes and
> have '<sml:attribute>' instead".

I missed the original letter,  suggesting such a thing....

I don't think it is reasonable. I think it's better to drop 
attributes, even they are very handy kludge - I think 
the cost is not worth it ( it was worth it in SGML, I think ).

>   Others say "lets
> remove comments and have 'comment' instead". This is
> not a simplification at all: the handling of these
> has to be handled by subsequent layers 

1. It *is* some simplification.
2. It makes the step forward.

Comments  are considered to be the part of the 
content.

Is it strong suggestion? Yes. Is it for sure wrong? 

I don't think so  - so  I'm writing a bit more on it, 
sorry if it would somtimes be not exactly about the 
comments, but I hope it is.
 
Actualy, Java already did the half-step in that direction, with 
javadoc. People enjoyed comments to become *more* 
than some verbal junk.  

Current situation with comments in XML ( and XML APIs) 
is very strange. On one hand they are part of the content 
( DOM works with them ) on another hand they are not
( SAX v 1.0 does not ). Inconsistensy. Isn't it ?
    
> (or, worst, by
> the programmer explicitly: will we have to put in
>     comment { display: none }
>     sml:attribute {display: none}
> into every CSS stylesheet?   

Unfortunately, for some reason I like XSL FO 
more than CSS, but I actualy see no big 
problem placing  

comment { display: none }

into every stylesheet. I am *already*  required 
to place many things into XSLT stylesheets, 
and also I  place #include <stdio.h> and 
use strict. It does not hirt me. 

But.

Maybe it would be handy to change 
current behaviour to ( 'what is not declared  - 
is not processed' ).  I mean that most of 
existing XML-related tools are dumping out 
everything they find in XML document if there 
is no command/instruction not to dump it. 

I don't think  it is good. It could be better 
to tune this behaviour with  

default { something }  

( if default is not defined - it is 'none'  ;-)

I don't  like HTML browsers 'silently fixing' 
my HTML, I don't  like compilers  silently 
initializing my variables to 0 and stuff like that.

If it is not decalred  - don't  initialize it. 
If it is not set for being drawn - don't draw it, 
because if you do ( like current HTML 
browsers do ) -  it  gives  the user an  impression 
that everything is fine in the situation when 
everything is *not* ( like it is with initialization 
with 0 ).

Unfortunately, it is a bit not related to the 
comments, but I just had to say that  things 
could be done in a bit different way with 
comments ( so you will have no need to 
write especial rule for comments. Or you 
will need only if you decided to write
default: { something here } ).

Rgds.Paul.




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