Janknerics 0.0.16

Janknerics

An alternative to built in generics. With a couple bonus features.

Basics

Instead of writing:

class MyGeneric<T1, T2, T3, T4>
{
    public T1 P1;
    public required T2 P2 { get; init; }
    public T3 P3;
    public T4 P4;
}

class MyClassFloats: MyGeneric<float, float, int, string>;
class MyClassDoubles: MyGeneric<double, double, long, string>;
class MyClassAllInts : MyGeneric<int, int, int, int>;

Which is simple enough when there are not many types but...

With Janknerics we can write:

partial class MyClassDoubles;
partial class MyClassAllInts;

class MyModelClass
{
    [Jankneric(typeof(MyClassDoubles), NewType = typeof(double))]
    [Jankneric(typeof(MyClassAllInts), NewType = typeof(int))]
    public float P1;
    
    [Jankneric(typeof(MyClassDoubles), NewType = typeof(double))]
    [Jankneric(typeof(MyClassAllInts), NewType = typeof(int))]
    public float P2 { get; }
    
    [Jankneric(typeof(MyClassDoubles), NewType = typeof(long))]
    [Jankneric(typeof(MyClassAllInts), NewType = typeof(int))]
    public int P3;
    
    [Jankneric(typeof(MyClassDoubles), NewType = typeof(string))]
    [Jankneric(typeof(MyClassAllInts), NewType = typeof(int))]
    public string P4;
}

This takes more lines of code BUT it's much easier to follow when the number of type parameters gets large.

Bonus Features

Since Janknerics is a Source Generator we can make it a little more useful than plain Generics too.

Properties can be omitted entirely or "passed through" exactly.

In the example above for the P4 field we could have written:

    [Jankneric(typeof(MyClassDoubles))]
    public string P4;

In this case:

• MyClassDoubles will have
  • public string P4; (just like MyModelClass)
• MyClassAllInts
  • will not have a P4 at all.

Constructors can be optionally autogenerated

In the example above the attributes on MyModelClass could have been specified this way:

[JanknericConstructor(typeof(MyClassDoubles))]
[JanknericConstructor(typeof(MyClassAllInts))]
class MyModelClass

In this case:

• MyClassDoubles gets a constructor that takes a MyModelClass argument.
  • each Property in MyClassDoubles will be constructed (and/or initialized?) with the corresponding property in MyModelClass
• MyClassAllInts gets a constructor that takes a MyClassDoubles argument.
  • each Property in MyClassAllInts will be constructed (and/or initialized?) with the corresponding property in MyClassDoubles