I appreciate your inquiry about "lens" within the realm of .NET Standard technology. In this context, "lens" refers to a concept often associated with functional programming and immutable data manipulation. In .NET Standard, lenses are typically implemented as a way to efficiently modify immutable objects without changing their original state.
A lens can be represented as a pair of functions: one for getting the value from an object, and another for setting the value in the object while returning a new modified copy. This approach ensures that the original object remains unchanged, promoting immutability and maintaining data integrity.
Here's a simplified example using C#:
public class Lens<T, V>
{
private readonly Func<T, V> getter;
private readonly Func<T, V, T> setter;
public Lens(Func<T, V> getter, Func<T, V, T> setter)
{
this.getter = getter;
this.setter = setter;
}
public V Get(T obj) => getter(obj);
public T Set(T obj, V value) => setter(obj, value);
}
Using the lens:
public class Person
{
public string Name { get; set; }
}
var nameLens = new Lens<Person, string>(p => p.Name, (p, name) => new Person { Name = name });
var person = new Person { Name = "John" };
var newNamePerson = nameLens.Set(person, "Doe");
In this example, the `nameLens` encapsulates the access and modification of the `Name` property. When using `nameLens.Set`, a new instance of `Person` is returned with the modified name, leaving the original `person` instance unaffected.
This allows for predictable and controlled manipulation of immutable data, which is crucial when dealing with concurrency and maintaining data consistency.
I hope this explanation sheds light on the concept of lenses in the context of .NET Standard technology. If you have further questions or need additional examples, feel free to ask!