R: Control characters in Description or Comments fields?

Doug Ewell doug at ewellic.org
Fri Feb 27 17:45:37 CET 2015

Addison Philips wrote:

> No, that's not correct: the ABNF grammar for the registry does not
> permit the C0 controls except where CRLF is *explicitly* required. See
> section 3.1.1. Although the text is permissive, the grammar is not--on
> purpose.

I skipped right over the ABNF in Section 3.1.1. Should have known

For purposes of representing the Registry in a format other than
record-jar, the CRLF provisions can be disregarded, as they exist to
allow folding lines on boundaries of 72 UTF-8 bytes, which no other
common format requires.

> I can't think of a reason we would ever allow a registration to occur
> with those (or their C1 control friends) anyway. Controls would only
> appear if someone (well, specifically *YOU*) were to submit a record
> containing same. I would never support such a registration.


> I suppose it is possible for other non-graphic Unicode control
> characters to occur. For example, a mixed direction description might
> use one of the isolation or direction control characters (with &pdf;)
> or one might see a variation selector, ZWJ, ZWNJ, etc. in a non-Latin
> sequence in certain languages.

Fortunately, since I'm dealing specifically with JSON in this case, I
don't have to worry about any of those, or even the C1 controls.

Doug Ewell | http://ewellic.org | Thornton, CO 🇺🇸

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