Re: [xml] XML guidelines

[Rush Manbert <rush manbert com>]

Norberto Lopes wrote:
> I'm having some difficulties deciding the best way to describe what I
> want, being the best given by efficiency when searching the tree and
> adding or removing elements.
>
> Which one do you think is best?
>
> 1st one:
> <example>
>   <sum>2+1</sum>
>   <sum>3*2</sum>
>   <div>3/2</div>
>   <div>1/2</div>
>   <mult>3*5</mult>
>   <mult>5*9</mult>
> </example>
>
> 2nd one:
> <example>
>   <sums>
>     <sum>2+1</sum>
>     <sum>3*2</sum>
>   </sums>
>   <divs>
>     <div>3/2</div>
>     <div>1/2</div>  
>   </divs>
>   <mults>
>     <mult>3*5</mult>
>     <mult>5*9</mult>
>   </mults>
> </example>
>
> Or should I just use which I think is best? Are there some guidelines
> or concerns with this? I couldn't find any info on this, or if it is
> something I should worry when writing big xml files.
>
> Thanks in advance for any information.

Hi Norberto,

Unless your xml doc is really huge, my guess is that either way works 
equally well as far as the parser is concerned. From a flexibility point 
of view, I would avoid the second approach, because the enclosing 
<sums></sums>, etc. elements really don't add anything, and they 
preclude you from doing some things.

I would even suggest that in the first case, you would change the syntax 
to something like:

<sum>
    <item>2</item>
    <item>1</item>
</sum>

or maybe:

<sum>
    <item val=2 />
    <item val=1 />
</sum>

because the operators are implied by the enclosing <sum> elements. (And 
I suspect that you might run into parsing problems, depending on the 
processor, with the division operator because it's a special character 
in the context of an element.)

But even if you stick with what you have, a reason to use your first 
approach is that it lets you write equations like:

5 * (20/(17+34))

in the form

<mult>5*
    <div>20/
        <sum>17+34</sum>
    </div>
</mult>

which you might not want to do today, but which you can't do tomorrow if 
you use your second form.

Best regards,
Rush