[xsl] are all strings in a sequence valid potential QNames

[ac <ac@xxxxxxxxxxxxx>]

Hi List,

As for example, in determining element and/or attribute names from the 
first line of a csv file, as well as other similar cases, with xslt2.0 
(e.g. without "map", "try", and schema), what is the best way to check 
(e.g. true/false) that
1. a string is a valid potential QName (e.g. match + what regex?, or 
other option)
2. all strings in a sequence are valid potential QNames

Thank you,
ac