Re: [xml-dev] newline/form feed valid as attribute value?

[Michael Kay <mike@saxonica.com>]

It's theoretically impossible to write an XML parser using regular 
expressions alone, because XML is not a regular language.

Form feed and vertical tab are valid characters in XML 1.1 attributes, 
but they must be written as numeric character references. They are not 
allwoed in XML 1.0.

Newline characters (xA) may appear in XML 1.0 attributes and the parser 
is required to normalize them to space characters, unless they are 
written as numeric character references.

Michael Kay
Saxonica



On 02/07/2012 19:48, Dan Shelton wrote:
> 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?
>
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