Patrick Drechsler <patrick@pdrechsler.de> writes:

> is the attached xml file (simple.xml) really invalid (as indicated by
> nxhtml) or is this a bug in nxhtml?

The file simple.xml is really invalid.

http://www.w3.org/TR/2006/REC-xml-20060816/#sec-prolog-dtd

The XML spec gives the following syntax description for the prolog of an
XML file (I've only copied the relevant parts):

    [3]    S	    ::=  (#x20 | #x9 | #xD | #xA)+
    [22]   prolog   ::=  XMLDecl? Misc* (doctypedecl  Misc*)?
    [23]   XMLDecl  ::= '<?xml' VersionInfo EncodingDecl? SDDecl? S? '?>'

Note that there is no S before the literal “<?xml" and that "<?xml" is
optional.

So, yes, an file that contains whitespace before "<?xml" is invalid XML.

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