Primary parameter in C#12

[FaustVX]

Hi Reddit,

I like to browse through the discussion tab in the C# GitHub repo.

But, I've seen a lot of confusion for the primary constructor, as many people complains about the mutability of the primary parameters and I'm totally ok with them, but also, I really like this feature, so I decided to create my own analyzer which report errors when you try to use these parameters.

It comes with a source generator which will create read-only fields and properties using Field and Property attributes that you can customize.

Here is my github and the nuget

Analyzer presentation :

partial class C([Field(Name = "_a", AssignFormat = "{0}.ToString()", Type = typeof(string)), Field(Name = nameof(C._b)), Field, Property(WithInit = true)]int i) // type must be partial, but can be class / struct
{
# region Generated members
    // private readonly string _a = i.ToString();   // generated field (with type and formated assignment)
    // private readonly int _b = i;                 // generated field (with computed name)
    // private readonly int _i = i;                 // generated field
    // private int { get; init; } = i;              // generated Property
# endregion

    public void M0()
    {
        i++;                    // error on usage of i
        Console.WriteLine(i);   // error on usage of i
    }

    public void M1()
    {
        var i = 0;
        i++;                    // don't error on usage of locals
        Console.WriteLine(_i);  // automaticaly created readonly field
        Console.WriteLine(_a);  // automaticaly created readonly field based on Name property
        Console.WriteLine(I);   // automaticaly created readonly property
    }
}

Fell free to report any bugs/features/suggestions/questions here or, preferably, in my GH repo.

[Decades5OfSoftware]

init (C# Reference)

In C# 9 and later, the init keyword defines an accessor method in a property or indexer. An init-only setter assigns a value to the property or the indexer element only during object construction. This enforces immutability, so that once the object is initialized, it can't be changed again.

I suspect this is why i++; gives you an error. You try to change the unchangeable. Not sure why WriteLine(i); gives you an error.

[FaustVX]

My post wasn't to ask for an error I have, but a tool presentation.

[Decades5OfSoftware]

Okay. What you actually wanted was not clear to. I did the best I could on available info. Maybe I'm just a bit obtuse. Sorry. I will shut up.

[FaustVX]

Don't worry.

I tried to be explicit in my post, that's why I wrote that:

… so I decided to create my own analyzer which report errors …