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Re: XPath expression which checks that all commas are escaped

• From: Dimitre Novatchev <dnovatchev@gmail.com>
• To: "Costello, Roger L." <costello@mitre.org>
• Date: Fri, 3 Nov 2017 12:14:51 -0700

not(contains(replace(., '\\,', ''), ','))

On Fri, Nov 3, 2017 at 11:40 AM, Costello, Roger L. <costello@mitre.org> wrote:
> Hi Folks,
>
> Do you deal with Request for Comments (RFCs)? Then the following might come
> in handy someday.
>
> Note: Thanks to Martin Honnen for helping me with the XPath expression
> (below).
>
> Some RFCs (e.g., vCard) have this rule:
>
>
>
>                 Each comma in a value must be escaped with a backslash.
>
>
>
> Examples:
>
>
>
> This value is good:
>
>
>
> A\, B
>
>
>
> This value is bad:
>
>
>
> A, B
>
>
>
> This value is also bad, because one comma is escaped but the other is not:
>
>
>
> A\, B, C
>
>
>
> Suppose the RFC has an XML representation. Or, you have used something like
> DFDL to convert the data to XML.
>
> Then, this XPath expression checks to see that each comma is properly
> escaped:
>
> every $token in tokenize(., ',')[position() lt last()] satisfies
> ends-with($token, '\')
>
>
>
> That XPath expression can be used in Schematron like this:
>
> <sch:pattern id="Escaping-Rules">
>
>     <sch:rule context="value">
>
>         <sch:assert test="every $token in tokenize(., ',')[position() lt
> last()] satisfies ends-with($token, '\')">
>             A COMMA character in a value MUST be escaped with
>             a BACKSLASH character (U+005C).
>         </sch:assert>
>
>     </sch:rule>
>
> </sch:pattern>



-- 
Cheers,
Dimitre Novatchev
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Truly great madness cannot be achieved without significant intelligence.
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To avoid situations in which you might make mistakes may be the
biggest mistake of all
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Quality means doing it right when no one is looking.
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-------------------------------------
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write all patents, too? :)
-------------------------------------
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I finally figured out the only reason to be alive is to enjoy it.

• Follow-Ups:
  • Re: XPath expression which checks that all commas are escaped
    • From: Dimitre Novatchev <dnovatchev@gmail.com>

• References:
  • XPath expression which checks that all commas are escaped
    • From: "Costello, Roger L." <costello@mitre.org>