what does "It's in BNF" mean ?

[PapaParrot]

In another topic, it was mentioned that the manual suggested was in BNF, I did not know what that means, so looked , using the same key words as my topic title,. I found the results interesting, since I was not aware of the term, Backus-Naur Form (BNF)

http://matt.might.net/articles/grammars-bnf-ebnf/

The language of languages
----snip---

Languages form the terrain of computing.

Programming languages, protocol specifications, query languages, file formats, pattern languages, memory layouts, formal languages, config files, mark-up languages, formatting languages and meta-languages shape the way we compute.

So, what shapes languages?

Grammars do.

Grammars are the language of languages.

Behind every language, there is a grammar that determines its structure.

This article explains grammars and common notations for grammars, such as Backus-Naur Form (BNF), Extended Backus-Naur Form (EBNF) and regular extensions to BNF.

After reading this article, you will be able to identify and interpret all commonly used notation for grammars.
----snip---, really worth reading, if you did not all read know about this---

So any way, figured it would be better in offtopic, rather then de-railing the topic where I saw the term for my first time,..

[jggimi]

For clarity*, PappaParrot is referring to this post:

Originally Posted by jggimi

There's a GRAMMAR section at the end of the pf.conf(5) manual. It's in BNF, so can be difficult to comprehend ... but sometimes I find it can be helpful when I get unexplained syntax errors.

* BNF isn't necessarily human-readable.

[IdOp]

Thanks for looking it up and sharing the result PapaParrot, I hadn't heard the term either.