newline/form feed valid as attribute value?

[Dan Shelton <dan.f.shelton@gmail.com>]

Does anyone here know whether newlines, form feed or vertical feed are
valid within an attribute value (I hope not, otherwise it would make
it a lot harder to write a fast xml parser using regex alone)?

---------- Forwarded message ----------
From: Dan Shelton <dan.f.shelton@gmail.com>
Date: 1 July 2012 17:35
Subject: Re: newline/form feed valid as attribute value?
To: xml@gnome.org


On 1 July 2012 17:06, Dan Shelton <dan.f.shelton@gmail.com> wrote:
> In which context are newlines valid values, i.e. is a newline
> character or a form feed a valid character in an attribute value?

Clarifying the question:
Is this a valid xml fragment:
-----cut-----
<mytag myattribute="hello
 world">sometext</mytag>
-----cut-----
Or as UNIX(TM) shell code:
/usr/bin/printf '/<mytag myattribute="hello \n world">sometext</mytag>'

Same with form feed:
/usr/bin/printf '/<mytag myattribute="hello \f world">sometext</mytag>'
Is this valid?

Or with vertical feed:
/usr/bin/printf '/<mytag myattribute="hello \v world">sometext</mytag>'
Is this valid?