Re: [VCARDDAV] Escaping dquote in a parameter value

[Simon Perreault <[e-mail]>]

Interesting. I follow your reasoning and agree with your conclusion.

Have you actually come across a parameter value that needed to contain a 
dquote?

Simon

On 2012-06-19 22:56, Cyrus Daboo wrote:
> Hi,
> As I am sure most people are aware, a double-quote character is
> forbidden to appear in a parameter value in both vCard and iCalendar.
> Yet there is a need to preserve double-quotes in a parameter value. So I
> am going to propose an extension to the specifications whereby a new
> escape mechanism is introduced solely for the purpose of allowing
> d-quote in a parameter value in a backwards compatible manner.
>
> My proposal is to use ^ (0x5e) as an escape character, with only the
> following two sequences allowed:
>
> ^^ - represents a single ^ character
> ^' - represents a single d-quote character
>
> I ruled out use of \ because some parsers erroneously eat that, and it
> would also be tempting to use \" which is definitely not possible
> because the dquote cannot appear.
>
> I also ruled out & (XML/HTML entity style) and % (URI style) style
> escaping as being too general - we don't need to escape arbitrary
> characters - only dquote. Also, I think & and % are already in common
> use in parameter values that have URIs, so would end up being escaped
> themselves a lot more. I suspect ^ is one of the least used characters
> and so the need to escape the escape character is less.
>
> Obviously there would need to be some backwards compatibility statement
> in regard to what to do with existing values with a single ^. I would
> suggest any combination that is not one of the above two, should be left
> alone when parsing. But when generating, it would be escaped as ^^.
>
> There are probably some other ascii symbols that are infrequently used
> too, that we could pick if there are strong arguments against ^, but for
> now I am happy with ^.
>
> Thoughts?
>


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