[myco_logic]

If you're talking about the curly braces after the backtick in the syntax diagram for operators, I think that's just a way to escape those special characters so you can use them in operator names. It would be the same as escaping a double quotation mark in a string literal with a backslash, i.e: "\""

[Garlef]

Merci. Thets also the explanation I came up with for myself. And I guess it allows for some trickery with unquoting.