Support for IETF ABNF (RFC 5234 and extensions)

[reschke]

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[reschke]

I submitted the CLA.

[googlebot]

CLAs look good, thanks!

[mikesamuel]

I'm pretty sure (-[A-Za-z0-9]+|[\.[A-Za-z0-9]+]*) doesn't do what you want. Notice the [ and ] around \.[A-Za-z0-9]+ instead of parentheses.

Maybe (?:[-.][A-Za-z0-9]+)* does what you want.

If so, this problem occurs thrice.

Also, AFAICT, %s doesn't appear in RFC 5234. Is that part of an extension? Do those conventions include an escaping convention for strings?

[reschke]

1. Will check.
2. %s is defined in https://tools.ietf.org/html/rfc7405#section-2.1 (but so is "%i" which I should include as well)

[reschke]

I tried to address this in d8a2671 - note that the simplified expression would match things like

%x31-39-49

which it should not (but then one could argue that it's not the job of the highlighter to spot errors like these).

[reschke]

Note I have added a few tests/examples in https://greenbytes.de/tech/webdav/rfc2629xslt/testcase.html#abnf.support

[reschke]

@mikesamuel - anything else that needs to be done to get this PR accepted? For now, in my IETF doc generation tool, I simply add the code in the generated document; see reschke/xml2rfc@1b0a090

[reschke]

Ping?