Use flags enum as replacement for missing c# 'in'-operator

[Olivier J]

This is actually an answer to an old post which is closed. But it may nevertheless be useful to someone.

Old Post: Has if () syntax of C# no IN operator like Pascal or SQL (IN, LIKE,BETWEEN)?

Good, short and fast possibility is to define the enum as flags, like e.g.:

[Flags]
internal enum TokenType
{
    Empty = 0,
    LBrace = 1,
    PlusLBrace = 2,
    RBrace = 4,
    LBracket = 8,
    RBracket = 16,
    Period = 32,
    RecordID = 64,
    Rubbish = 128,
 
    TermStartSymbols = RecordID | LBrace | PlusLBrace | LBracket 
}

You can then test for a flag like this:

while ((CurrentToken.Type & TokenType.TermStartSymbols) != TokenType.Empty) {
    sequence.Add(Term());
}

Note that TokenType.Empty must be defined as 0.