Are XML/HTML tag names inside closing tags really necessary?

Question

This is really not a programming question per se, but I was wondering why the name of the tag is required in a closing tag in XML. For instance, couldn't

<a>
    <b>stuff</b>
</a>

Be written

<a>
    <b>stuff</>
</>

So that each closing tag </> merely terminated the last opened tag?

So my questions are

1. Would this work (i.e. are there any corner cases I'm not thinking of in which this would be ambiguous/fail)?
2. If it would work, why didn't 'they' design it that way?

Answer 1

If it would work, why didn't 'they' design it that way?

One reason is that SGML/XML are also designed to be human readable. Your /a/b example is readable, but a structure much more complex would be a nightmare to try to interpret.

This would especially be true with mixed content (PCDATA and element structures mixed).