Using In-Line Lambda functions as an argument

Question

I am optionally display some content in the Unity Editor based on options chosen for a given component, this will be used when displaying a summary of options chosen on this current Component.

How I can make a function inline that returns a string, I want this function to be inline because there will be many of these and they will only useful in the line they are used in.

I have provided a code snippet that may clarify what I am trying to do.

I have used lambda functions like this in c++ and JavaScript, but not in c# and I've tried finding an answer on how to use them like this in C#.

var script = target as ButtonManager;//get reference to this Component 

EditorGUILayout.LabelField("Your current Interactive configuration", 
            "Parent: " + script.sceneParent.name + "\n",
            "Popup? " + ()=>{ if (script.isPopup) { return "Popup" } else { return "Change Scene"} }
            + "\n"
            );

Edit: I can use a ternary operator to solve this problem, but I am curious as to how this would work with lambda functions.

score 2 · Accepted Answer · answered Jul 10 '19 at 03:51

To use a delegate inline in your string concatenation you need to create a new Func<string> from the anonymous method and execute it:

EditorGUILayout.LabelField("Your current Interactive configuration", 
            "Parent: " + script.sceneParent.name + "\n",
            "Popup? " + new Func<String>(()=>{ if (script.isPopup) { return "Popup"; } else { return "Change Scene";} })()
            + "\n"
            );

yuk. You also need to consider things like variable closure. All that to say that the ternary operator is a cleaner solution here.

Thank you, although not practical here. Its very good to know if ever I run into a situation where this is clean and easy. Cheers! — Aiden Faulconer, Jul 10 '19 at 03:55

Salah Akbari · Answer 2 · 2019-07-13T02:42:44.987

1

What about the ternary operator. Something like this:

return script.isPopup ? "Popup" : "Change Scene";

This could be also helpful https://stackoverflow.com/a/38451083/2946329

edited Jul 13 '19 at 02:42

answered Jul 10 '19 at 03:14

Salah Akbari

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Thank you, I thought about this but didn't know if it would work as an argument. Just tried it, cheers – Aiden Faulconer Jul 10 '19 at 03:16
@AidenFaulconer This could be also helpful https://stackoverflow.com/a/38451083/2946329 – Salah Akbari Jul 10 '19 at 03:25
Thats clever, never thought about instantiating a type Action inline... I'd post that as an answer, or edit your current one – Aiden Faulconer Jul 10 '19 at 03:29
One problem with the new Action(()=>) is that its void, how do you create an Action that has a return type? – Aiden Faulconer Jul 10 '19 at 03:46

score 1 · Answer 3 · answered Jul 10 '19 at 03:14

1

How about using ternary operator? instead of ()=>{ if (script.isPopup) { return "Popup" } else { return "Change Scene"} } use ((script.isPopup) ? "Popup" : "Change Scene").
Also you can use delegates

answered Jul 10 '19 at 03:14

Sohaib Jundi

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Delegates are awesome, but it may not be as convenient as just defining a temporary function inline. – Aiden Faulconer Jul 10 '19 at 03:18

Using In-Line Lambda functions as an argument

3 Answers3