On 18-May-25 09:19, Carsten Bormann wrote:
On 17. May 2025, at 22:36, Brian E Carpenter <[email protected]>
wrote:
However, RFC 9651 explains
exactly why it uses all that English:
" Appendix C. ABNF
This section uses the Augmented Backus-Naur Form (ABNF) notation [RFC5234] to
illustrate the expected syntax of Structured Fields. However, it cannot be used
to validate their syntax because it does not capture all requirements.”
I’m not sure that the text there accurately reflects what the authors wanted to
say.
I’m not aware of any ABNF anywhere that “captures all requirements”, so this is
a pretty weird argument.
(I already mentioned that “validating” the syntax is only a part of what needs
to be done here, so maybe they meant that — but that doesn’t make the ABNF any
less valuable.)
I agree with you. It's been pretty clear since BNF was first used (strictly
speaking, it was just BF for Algol 58, but that was well before my time) that
some terminations in BNF *require* explanation in human language. That doesn't
make the formalism useless.
Brian
_______________________________________________
rfc-interest mailing list -- [email protected]
To unsubscribe send an email to [email protected]
