In XSLT/XPath, how do I get the first attribute that doesn't match a specific name?

Question

I have this snippet of XSLT code:

<xsl:variable name="key" select="@*[1]"/>

But I need it to actually set key to be the first attribute (if it exists) that doesn't have a special name. So both of these nodes would have the same key, and special_attr is ignored if it exists.

<MyNode var="1" />
<MyNode special_attr="foo" var="1" />

What is the proper select syntax to get the first attribute's value whose name isn't special_attr?

Answer 1

<xsl:variable name="key" select="@*[not(name() = 'special_attr')][1]"/>