Expression Guard

[ardalis]

An Expression-based Guard could be used to provide flexibility and could cover any case not already taken care of by the library, without the need to write your own guard clause method.

public static T AgainstExpression<T>([JetBrainsNotNull] this IGuardClause<T> guardClause, [JetBrainsNotNull] Func<T, bool> func, [JetBrainsNotNull] string message) where T : struct
{
    if (func(guardClause.Value))
    {
        throw new ArgumentException(message);
    }
    return T;
}

[fiseni]

This is nice. Any reason you want to limit this only for "struct"?

[dsbert]

Be aware that this can lead to performance issues if abused.

safakgur/guard#13

[ardalis]

Let's implement this and see if there are any issues.

[mohaanwrites]

If someone wants to deal with string properties with custom validations, this will not allow. Otherwise, I've added the required tests. Let me know. @ardalis

[wgnf]

@ardalis do you still want this to be implemented? if so, i'd love to have a go at this :)

[ardalis]

yes, if someone wants to implement support for it, I'd look at the PR. Just reference this issue number in the description. Thanks, @wgnf

[wgnf]

Just scrolling through code to see how things are done i stumbled upon this one:

https://github.com/ardalis/GuardClauses/blob/main/src/GuardClauses/GuardClauseExtensions.cs#L581-L589

Guard.Against.InvalidInput seems to already be the "Expression Guard" that you want to implement in this issue 🤔

[wgnf]

The only thing that is different here is that you mention a IGuardClause<T> with a Value in that (new) interface, which I'm unable to find.

Or is that the new feature you wanted to implement and I just didn't get the hint? :D @ardalis

[ardalis]

Hmm... yeah, that's fair. I think maybe I missed it due to its naming. Ok, let's just say this is done, then. 😃