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Questions tagged [abnf]

Augmented Backus–Naur Form (ABNF) is a metalanguage based on Backus–Naur Form (BNF)

In computer science, Augmented Backus–Naur Form (ABNF) is a metalanguage based on Backus–Naur Form (BNF), but consisting of its own syntax and derivation rules. The motive principle for ABNF is to describe a formal system of a language to be used as a bidirectional communications protocol.

via: Wikipedia

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Is there a metalanguage, similar to BNF that can concisely describe self-describing data?

Say for instance I had a data set that was self describing. The first few well-structured records define data type IDs, which include the name and length of records, followed by content records, which start with the data IDs and contain a variable…
Mike Godin
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Expanding SPF macros

I'm trying to implement a check_host function based on the SPF RFC7208. It is almost ready and the thing that has left is the macro expansion detailed in section 7 (https://www.rfc-editor.org/rfc/rfc7208#section-7). I know there are readily…
Ivo Andonov
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Does the order of rules in ABNF matter?

Does the order of rules in Augmented Backus-Naur Form matter? In particular, are a = b b = c and b = c a = b the same? What about a = b a =/ c and a =/ c a = b ? Would it be possible to have a rule using =/ without a rule of the same name using…
Xandaros
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Is it acceptable for the qvalue to be "1." or "0." based on RFC7231 (HTTP 1.1)?

Is it acceptable for the QVALUE to be "1." or "0." in, say, the Accept-Language header? e.g. Accept-Language: en;q=1. or Accept: text/plain;q=0. RFC7231 (and RFC2616) which specifies the ABNF for QVALUE as follows: weight = OWS ";" OWS "q="…
ioquatix
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Parse::ABNF perl usage

I need to parse the SIP headers (grammar in ABNF format) and verify if my Header strings are ok or not. (Example: check strings like "Accept: application/sdp,application/3gpp-imp+xml" to provide testcase pass/fail). Currently I am trying to use…
user3336154
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Optional sequence rule clarification

3.8. Optional Sequence: [RULE] Square brackets enclose an optional element sequence: [foo bar] is equivalent to *1(foo bar). The above section from RFC5234 seems not correct to me. I think this is because the optional…
canoe
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What is the proper way to encode an AMF0 StrictArray

After overviewing the AMF0 specification I find that I cannot understand the proper way to encode the StrictArray type. Here is the most immediate section of the specification: array-count = U32 strict-array-type = array-count *(value-type) which…
Emily Mabrey
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The complex ABNF rule converts to a regex

This is hard to me. How to convert below ABNF rule to a regex? *((*LF *CR *(\x0 / text) *CR *LF) / CRLF)
canoe
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