Case conventions on element names?

Question

Are there any formal recommendations on element casing in XML?

I know XHTML uses lowercase element names (as opposed to HTML which canonically uses uppercas

Answer 1

To expand on my comment above: the use of 'lowercase with hyphens' has some problems in XSLT. Specifically it is easy to confuse a node called, say, 'year-from-age' with a formula 'year - age' (e.g. subtract age from year).

As @KarlKieninger points out, this is only a problem at the human level and not for the XSLT parser. However since this will often not produce an error, using 'lowercase with hyphens' as a standard is asking for trouble, IMHO.

Some pertinent examples:

11

outputs 2, as expected

11

DOES NOT ERROR, BUT OUTPUTS NOTHING AT ALL

In the above code, you must put at least one space before a subtraction operator, but there is no such requirement for an addition operator.

11

outputs 0, as expected

But note how confusing the above is to read!

132

outputs 3

132

outputs -1

The presence of a single space changes the output above, but neither variant is an error.