OK, I should have known I'd be challenged.

Here's my thinking. Although XML is often used for traditional two-dimensional row-and-column data, it doesn't have to be. It can have arbitrary levels of nestedness, extra dimensions.

So if you take this XML 

<items>
    <item>
        <foo>a</foo>
        <bar>b</bar>
        <baz>c</baz>
    </item>
    <item>
        <foo>x</foo>
        <bar>y</bar>
        <baz>z</baz>
    </item>
</items>

[download]
which follows this DTD: 
<!ELEMENT bar (#PCDATA)>
<!ELEMENT baz (#PCDATA)>
<!ELEMENT foo (#PCDATA)>
<!ELEMENT item (foo, bar, baz)>
<!ELEMENT items (item+)>

[download]
Yes, it's pretty much plain sailing to generate the HTML.

But what about this? 

<items>
    <item>
        <foo>a</foo>
        <bar>b</bar>
        <baz>c</baz>
        <item> <!-- items can contain sub-items -->
            <foo>d</foo>
            <bar>e</bar>
            <baz>f</baz>
        </item>
    </item>
    <item>
        <foo>x</foo>
        <bar>y</bar>
        <baz>z</baz>
    </item>
</items>

[download]
Which matches the DTD with one small change: 
<!ELEMENT bar (#PCDATA)>
<!ELEMENT baz (#PCDATA)>
<!ELEMENT foo (#PCDATA)>
<!ELEMENT item (foo, bar, baz, item?)>
<!ELEMENT items (item+)>

[download]

What's my HTML form going to look like when any given <item> element can contain an arbitrary number of other <item> elements?


Nobody says perl looks like line-noise any more
kids today don't know what line-noise IS ...

In reply to Re^3: Going between XML and Cgi by way of DTD by Cody Pendant
in thread Going between XML and CGi by way of DTD by throop

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