Nondestructive mutation: tell me about a time
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often, because a lot of common bugs can be traced back to unexpected mutations so if you send me an object and I don't know where it comes from, and I need a modified version of that to do something else, I'll make a copy first - I might use `.DeepClone()` from [NuGet Gallery | PeanutButter.Utils 3.0.167](https://www.nuget.org/packages/PeanutButter.Utils) followed by some (again, from that lib) `.With(...)` statements, eg ``` var foo = yourObject.DeepClone() .With(o => o.Name = o.Name.ToUpper()); ```
------------------------------------------------ If you say that getting the money is the most important thing You will spend your life completely wasting your time You will be doing things you don't like doing In order to go on living That is, to go on doing things you don't like doing Which is stupid. - Alan Watts https://www.youtube.com/watch?v=-gXTZM\_uPMY
That is a great example that I understand better now because I watched the video: Coding Shorts: For The Record - Why You Should Use (Records in C#) - YouTube[^] Shawn Wildemuth (who is a great trainer and has created some top videos on PluralSight)
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Graeme_Grant wrote:
I find them useful as DTOs or for simple POCOs.
That makes a lot of sense to me. I will check out the video. Thanks
raddevus wrote:
I will check out the video. Thanks
Nick is very good. He deep dives and is very thorough.
Graeme
"I fear not the man who has practiced ten thousand kicks one time, but I fear the man that has practiced one kick ten thousand times!" - Bruce Lee
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Just reading up on the new C#
recordkeyword and nondestructive mutation[^] and wondering: When was a time you used this concept? Anyone? Anyone...? Bueller...? Bueller...? Just curious.I use this all the time. The naming is a little odd, but the concept is very simple: Copy an object and then change just those fields and properties you need to change. Seriously, I'm not sure this is useful as syntactic sugar except in very limited cases.
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Just reading up on the new C#
recordkeyword and nondestructive mutation[^] and wondering: When was a time you used this concept? Anyone? Anyone...? Bueller...? Bueller...? Just curious.It's excellent for data contracts in web services where the reception is generally out of the client's control and whatever comes in the response, that is the object, because that is what came and it should probably never be mutable. The bottom line is that record can help enforce SOLID adherence. Many POCOs in general should now probably be defined as records instead of class. They're great. The only drawback/beef I have with them is having to do hokey workarounds to use them while targetting .NET Standard (C# 9–Use Record types in .NET Standard 2.0[^]).
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Just reading up on the new C#
recordkeyword and nondestructive mutation[^] and wondering: When was a time you used this concept? Anyone? Anyone...? Bueller...? Bueller...? Just curious.Have I (to your point) occassionally has a use for this?...Yes. Is this overkill?...Yes. This is what you get when you open source things and can't think of a compelling reason to say "no". That being said there ARE some useful things that have come from the open sourcing. BTW, Top Level command NOT being one of them! :-)
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Just reading up on the new C#
recordkeyword and nondestructive mutation[^] and wondering: When was a time you used this concept? Anyone? Anyone...? Bueller...? Bueller...? Just curious.This feature is useful to avoid all kind of bugs related to the usage of mutable values with multiple ownership shared through references. Think about scenarios when a method 'foo' receives an object as an input parameter. The initial contract is that the object's fields are not changed inside 'foo' . In a big codebase there would be many places where 'foo' becomes used over time, with the semantics of not changing the fields of the input object. If at some point someone makes a change in 'foo' to mutate one of the fields, this could cause many non obvious problems. In practice, in complex codebases these problems might be difficult to detect in a code review. Immutable types and non destructive mutation provide a solution to better express this kind of semantic.
If you can't explain something to a six year old, you really don't understand it yourself. (Albert Einstein)
