About dotnet 6

So I read that 2017 has an upgrade to dotnet. I know nothing about that new version since I learned c# on unity (jab jab) so can someone tell me how to make this code more succinct now? (something to do withe ?= or ?.)

Code (CSharp):

1.         if (Time.time > timer)
2.         {
3.             timer = Time.time + 1 / DPS;
4.             var rb = hit.rigidbody;
5.             if (rb)
6.             {
7.                 var unit = rb.GetComponent<Unit> ();
8.                 if (unit)
9.                     unit._health -= 1;
10.             }
11.         }

 

You can use null propagation to condense those checks to a single line.

Code (CSharp):

1. if (Time.time > timer)
2. {
3.     timer = Time.time + 1 / DPS;
4.     hit.rigidbody?.GetComponent<Unit>()?._health -= 1;
5. }

But if you don't know enough about those to know where to put them, I'd avoid them until you do. You're better off writing longer, more verbose code until you understand exactly what operators like "?." do.
You don't get any performance benefits or anything like that.

 

I highly doubt that the ?. operator works with Unity objects, such as Components.

Just like the ?? operator doesn't work with Unity objects. I filed a bug-report 824765 regarding the ?? operator a while ago:

QA replied with:

Therefore I'd be very surprised if Unity supports that ?. operator.

 

Indeed it's not safe to use though for a slightly different reason. == null is override for destroyed objects to check whether they are destroyed. GetComponent<> doesn't return destroyed objects though.

GetComponent<>() could just return an actual null. However, for the special 'Component could not be found' exception, in editor it returns a special object with an overridden == for null.

This is a bit of a mess and unity seems to be conflicted about it too:

https://gist.github.com/lucasmeijer/7475fd40ff6ac34c7c44
https://blogs.unity3d.com/2014/05/16/custom-operator-should-we-keep-it/

Personally I'm sad that they didn't fix this in the unity 5 cycle like proposed Especially the GetComponent<> wrapper could be removed, saving a ton of allocations in the editor too. Until then forum threads like these will keep popping up I guess!

 

Yeah I never use them, and having someone who just discovered them want to abuse them is a major facepalm moment. This is pretty much the worst possible reason to be interested in upgrading! Clarity everyone!

Good advice

 

Love it, so concise but...

you are correct, it doesn't work. I just downloaded 2017 and tested this

Code (CSharp):

1.         var v = GetComponent<Camera>()?.GetComponent<Transform>()?.GetComponent<Rigidbody>().velocity;  
2.  

spits out that

Code (CSharp):

1. MissingComponentException: There is no 'Rigidbody' attached to the "Main Camera" game object, but a script is trying to access it.
2.  

I wonder if they could add an overload to the ?. operator to make this thing work.

 

Not without modifying the C# compiler unfortunately. That might not actually be too far out of reach with modern mono and Roslyn though, buuuut that'll be a while

 

Your code is incorrect though. You miss the ? after GetComponent<Rigidbody>(). What is the former two GetComponent for? I think you didn't have a clear learning for c# though. Not just the C# 6.

 

Quite right, I forgot that Unity overloads the == operator, which has bitten me on more than one occasion.
I really hope they do remove the overloaded operator. It's usefulness is limited and I'd rather feel silly for not adding a component once in a while that have permanent hacks in my code base to fix quirks.

In any case, this is exactly why you shouldn't really use things like ?. until you've firmly understood exactly what they do and where they should be used. This could have easily been made into a hard-to-track bug in your project.