How about new syntactical sugar for exception checking?

[Richard Deeming]

Foothill wrote:

To those of who still use pointers (even in .Net), using (*) might be a little confusing

And to those of us who use multiplication. :)

---

"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

[Richard Deeming]

How about something like this:

public abstract class DodgyResult<T>
{
public abstract bool Succeeded { get; }
public abstract T Value { get; }
public abstract Exception Error { get; }

public T GetValueOrDefault(T defaultValue = default(T))
{
    return Succeeded ? Value : defaultValue;
}

public static DodgyResult<T> Success(T value)
{
    return new SuccessResult(value);
}

public static DodgyResult<T> Failure(Exception error)
{
    return new ErrorResult(error);
}

// Explicit cast to the return type; 
// throws an InvalidOperationException if this is a failure result:
public static explicit operator T(DodgyResult<T> result)
{
    return result.Value;
}

// Allow the result to be treated as a bool value indicating success:
public static bool operator true(DodgyResult<T> result)
{
    return result.Succeeded;
}

public static bool operator false(DodgyResult<T> result)
{
    return !result.Succeeded;
}

private sealed class SuccessResult : DodgyResult<T>
{
    public SuccessResult(T value)
    {
        Value = value;
    }
    
    public override bool Succeeded => true;
    public override T Value { get; }
    public override Exception Error => null;
}

private sealed class ErrorResult : DodgyResult<T>
{
    public ErrorResult(Exception error)
    {
        Debug.Assert(error != null);
        Error = error;
    }
    
    public override bool Succeeded => false;
    public override Exception Error { get; }
    
    public override T Value 
    { 
        // Wrap the error in a new exception to preserve the original stack trace:
        get { throw new InvalidOperationException(Error.Message, Error); }
    }
}

}

public static class DodgyResult
{
// Helper to let the compiler infer the generic parameter:
public static DodgyResult<T> Success<T>(T value)
{
return DodgyResult<T>.Success(value);
}

public static DodgyResult<T> RunDodgy<T>(Func<T> dodgyFunc)
{
    try
    {
        return Success(dodgyFunc());
    }
    catch (Exception ex)
    {
        return DodgyResult<T>.Failure(ex);

[Dan Neely]

Why not make it a compiler flag that can be set once per file.

#pragma OnError ResumeNext

Did you ever see history portrayed as an old man with a wise brow and pulseless heart, waging all things in the balance of reason? Is not rather the genius of history like an eternal, imploring maiden, full of fire, with a burning heart and flaming soul, humanly warm and humanly beautiful? --Zachris Topelius Training a telescope on one’s own belly button will only reveal lint. You like that? You go right on staring at it. I prefer looking at galaxies. -- Sarah Hoyt

[TheGreatAndPowerfulOz]

Just NO!

#SupportHeForShe Government can give you nothing but what it takes from somebody else. A government big enough to give you everything you want is big enough to take everything you've got, including your freedom.-Ezra Taft Benson You must accept 1 of 2 basic premises: Either we are alone in the universe or we are not alone. Either way, the implications are staggering!-Wernher von Braun

[agolddog]

Chris Maunder wrote:

string result = DodgyApi.GetValue*();

What about string result = DodgyApi.GetValue*(value); as you don't always want the type default. Not sure how we define my value for reference types, maybe it could use the C# new type { prop1 = val1, ...} paradigm? Anyway, no, bad idea. I want to fire people who silently swallow exceptions. At least, the code should be logging at some level, "hey, DodgyApi failed, using default value x" so that (in theory) somebody could investigate and make the api somewhat less dodgy.

[Chris Maunder]

I just love to imagine the absolute mayhem such a pragma would allow.

cheers Chris Maunder

[englebart]

Don't use DodgyApi directly. string result = MyDodgyApiWrapper.GetValue(); Your wrapper can log any exceptions, provide a reasonable default value "Service unavailable. Try back later.", etc. If a better backend evolves later, just update your wrapper.

[Harley L Pebley]

If you make Run an extension method and rename it to IgnoreExceptions for clarity, you can say:

var s = (() => GetString(100)).IgnoreExceptions();

You can go one further and add another parameterized type for the catch's use to only ignore certain types of exceptions:

var s = (() => GetString(100)).Ignore();

[Lost User]

Too much time on your hands?

[BillWoodruff]

Excellent. Thanks for this example, Richard !

«There is a spectrum, from "clearly desirable behaviour," to "possibly dodgy behavior that still makes some sense," to "clearly undesirable behavior." We try to make the latter into warnings or, better, errors. But stuff that is in the middle category you don’t want to restrict unless there is a clear way to work around it.» Eric Lippert, May 14, 2008

[BillWoodruff]

Very interesting Nish, I was puzzled by the omission of a Type argument to NoEx.Run, and realize that my habit of always writing out the Type arguments wasn't necessary in this case. I've made a note to try and find more information on exactly when the compiler can infer the Type which renders including the Type an option. thanks !

«There is a spectrum, from "clearly desirable behaviour," to "possibly dodgy behavior that still makes some sense," to "clearly undesirable behavior." We try to make the latter into warnings or, better, errors. But stuff that is in the middle category you don’t want to restrict unless there is a clear way to work around it.» Eric Lippert, May 14, 2008

[Chris Maunder]

;)

cheers Chris Maunder

[Kiriander]

Swallowing excepsions is bad style. If the function throws different exceptions, there may be strong need to react to them differently.