How about new syntactical sugar for exception checking?

Chris Maunder

We get a shiny new "?" operator that takes

string result = null;
if (field != null)
{
result = field.Value;
}

and converts this to

string result = field?.Value

So what about the case where we're handling a flaky API

string result = null;
try
{
result = DodgyApi.GetValue(); // may throw an exception
}
catch
{
result = null;
}

What would you suggest we do for that? What about a headasplode (*) operator

string result = DodgyApi.GetValue*();

where GetValue* will silently swallow the exception thrown by GetValue and return default. Or am I setting a new standard for lazy, shameful programming here this hot, lazy afternoon?

cheers Chris Maunder

Richard Deeming

Seems like an awful idea to me - I want code that silently swallows exceptions to be a pain to write. However, you could always add the suggestion to the Roslyn GitHub repo[^] for discussion. It doesn't seem half as mad as some of the other suggestions on there! :)

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

realJSOP

On the "?" operator - I will strive NEVER to use that. On the head-asplode operator - Shouldn't that be

string result = DodgyApi.GetValue?*.();

And why aren't you working on my latest feature request?*.() And please don't say you simply haven't GOTTEN around to it yet.

".45 ACP - because shooting twice is just silly" - JSOP, 2010
-----
You can never have too much ammo - unless you're swimming, or on fire. - JSOP, 2010
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When you pry the gun from my cold dead hands, be careful - the barrel will be very hot. - JSOP, 2013

Corporal Agarn

John Simmons / outlaw programmer wrote:

And why aren't you working on my latest feature request?

He's waiting for the "?"

Mongo: Mongo only pawn... in game of life.

Lost User

Don't turn a nice language into an on-error-resume-next monster.

Bastard Programmer from Hell :suss: If you can't read my code, try converting it here[^][](X-Clacks-Overhead: GNU Terry Pratchett)

Vark111

How about a faux-extension method:

string result = DodgyApi.GetValue().OrDefault();

Then we can use it with LINQ as well to get rid of the ridiculousness of Single()/SingleOrDefault(), First()/FirstOrDefault() edit: After thinking about this a bit more, instead of syntactic sugar, isn't this one of the few raison d'être for the adapter pattern?

class DodgyApiAdapter: IDodgyApi {
    string GetValue() {
        try {
           string result = \_dodgyApiImpl.GetValue();
           return result;
        }
        catch {
           return null;
        }
    }
}

string result = dodgyApiAdapterInst.GetValue();

I mean if you're doing the empty-catch-returns-null pattern for an API enough to want syntactic sugar, then isn't an adapter warranted?

OriginalGriff

Headsplode does sound horribly like On Error Resume Next ... :~

Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...

Chris Maunder

I totally forgot about that! How about:

#pragma on error resume next

// ... code you wouldn't let your worst enemey near

Mwahaha

cheers Chris Maunder

Nish Nishant

You could always write a helper method.

string GetString(int x)
{
throw new NotImplementedException();
}

void Foo()
{
string s = NoEx.Run(() => GetString(100));
Console.WriteLine(s == null);
}

class NoEx
{
public static T Run<T>(Func<T> method)
{
try
{
return method();
}
catch
{
return default(T);
}
}
}

Not as clean as syntactic sugar, but fairly close :-)

Regards, Nish

Website: www.voidnish.com Blog: voidnish.wordpress.com

Kornfeld Eliyahu Peter

As an idea I despite code that swallows exception without trace... Also null sometimes your best friend (but not default), so why to eliminate!?

Skipper: We'll fix it. Alex: Fix it? How you gonna fix this? Skipper: Grit, spit and a whole lotta duct tape.

Ryan Peden

In this case, though, it's not really silently swallowing the exception. If the headasplode operator guarantees returning null on exceptions, then in using the operator your're explicitly expressing what you'd like to do if an exception occurs. It's more like exception handling shorthand than exception ignoring. :)

Richard Deeming

But with that operator, you've got to look closely at every method call to see whether or not it ignores exceptions. With the try..catch block, it's obvious what's happening. Also, how often do you really need to ignore every possible exception? Isn't it more likely that you'd want to ignore specific exception classes, and let unexpected exceptions propagate?

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

Ryan Peden

I agree that making things as obvious as possible is a good approach. How do you feel about the way Java handles this, where exceptions are part of the method signature, i.e. int addSomeNumbers throws Abc { }. And if you call a method that throws an exception, you have to either handle or rethrow (and add the throws clause to your method) if you want your code to compile. A lot of people seem to hate Java's checked exceptions, but if you're working on a big enough corporate code base, in which case there are probably at least a few lazy or marginally competent developers on the team, I can see the value in checked exceptions.

Richard Deeming

I can see the value, if they're done right. The temptation for lazy devs to add throws Exception is probably too high, though.

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

Brisingr Aerowing

Kornfeld Eliyahu Peter wrote:

I despite code

Quick Nitpick: that should be 'I despise code'. Despite means 'without being affected by; in spite of.', where despise means 'feel contempt or a deep repugnance for.'

What do you get when you cross a joke with a rhetorical question? The metaphorical solid rear-end expulsions have impacted the metaphorical motorized bladed rotating air movement mechanism. Do questions with multiple question marks annoy you???

Jorgen Andersson

This is a test, right?

Wrong is evil and must be defeated. - Jeff Ello

Foothill

To those of who still use pointers (even in .Net), using (*) might be a little confusing but I have an idea. How about using a construct similar to the for loop

// similar to...
for (int i = 0; i < limit; ++i) { ... }

// you can have
NoThrow (var <out>; Func<T>; <result on throw>);

// so your example becomes
string result;
NoThrow (result; dodgyApi.GetValue(); "I.M.Foo.Bar");

if (Object.DividedByZero == true) { Universe.Implode(); } Meus ratio ex fortis machina. Simplicitatis de formae ac munus. -Foothill, 2016

Joe Woodbury

"new" doesn't mean what you think it does.

Chris Maunder

Too explicit. We need something that truly, deeply hides what's going on ;)

cheers Chris Maunder

Foothill

If that's the end goal, just use a carrot (^) instead of equals. That way anyone the uses managed C++ is really hosed. :laugh:

string result ^ dodgyApi.GetValue();

if (Object.DividedByZero == true) { Universe.Implode(); } Meus ratio ex fortis machina. Simplicitatis de formae ac munus. -Foothill, 2016