[peteforde]

That's literally and exactly what I said.

[volemo]

To be fair to GP, I too was confused by your use of brackets here.

[peteforde]

I wasn't trying to be obtuse.

Formal grammar / technical documentation style guides consistently define:

[ ... ] = optional

{ ... } = repetition

| = alternatives

[IshKebab]

Hacker news isn't a formal grammar specification though. People use [1] for references here too (which you could easily have forgotten).