[oneplane]

One of the best representations of the 'simpleness' is the way you can draw it in a graphical loop diagram as they do on the json.org site.

When you can make your 'format' in to a not-too-big diagram like that it makes it far easier for anyone interested to 'get it' and encompass the whole thing in their mind to work with.

[koenigdavidmj]

SQLite is the place that (to my knowledge) was the first to do these "railroad diagrams". Here are all of theirs (though they're also available inside the documentation): https://sqlite.org/syntaxdiagrams.html

[rbonvall]

As far as I know, they were originally introduced by Niklaus Wirth to describe Pascal's syntax. See the last pages in this manual from 1973: https://www.research-collection.ethz.ch/bitstream/handle/20....

[jhrwalter]

They even go back to Algol 68: http://www.softwarepreservation.org/projects/ALGOL/book/Lind...

[heinrich5991]

Definitely not the first, I see that the first release of SQLite was 2000, and I found these railroad diagrams in old Pascal programming books of my father.

[1wd]

For example Turbo Pascal included a Language Guide book that documented the entire Object Pascal language with railroad diagrams:

https://archive.org/details/bitsavers_borlandturVersion7.0La...

[hans_castorp]

Oracle had those always (even back when only printed manual were available)