Function parse_option_list 

fn parse_option_list(
    cursor: &mut Tokens<'_>,
    options: &mut CopyOptionSet,
) -> PgWireResult<()>

Parses NAME [value] (, NAME [value])* until the closing ).

Option values are open-ended: a string literal, a number, an identifier or a boolean word. Whether an option makes sense is decided by the format codec, not here.