64 lines
2.6 KiB
C#
64 lines
2.6 KiB
C#
// Code quality of this file: low.
|
|
|
|
using System;
|
|
using System.Collections.Immutable;
|
|
|
|
public interface ILens<Hole, Whole> {
|
|
Whole Update(Func<Hole, Hole> update);
|
|
}
|
|
|
|
public sealed class ImmutableListLens<T, Whole> : ILens<ImmutableList<T>, Whole> {
|
|
public readonly System.Func<ImmutableList<T>, Whole> wrap;
|
|
public readonly ImmutableList<T> oldHole;
|
|
|
|
public ImmutableListLens(System.Func<ImmutableList<T>, Whole> wrap, ImmutableList<T> oldHole) {
|
|
this.wrap = wrap;
|
|
this.oldHole = oldHole;
|
|
}
|
|
|
|
// Put methods with the following signature here to focus on sub-parts of the list as needed.
|
|
// public ILens<ImmutableList<T>,Whole> sub-part => oldHole.sub-part.ChainLens(value => oldHole.with-sub-part(value));
|
|
|
|
public Whole Update(Func<ImmutableList<T>, ImmutableList<T>> update) => wrap(update(oldHole));
|
|
}
|
|
|
|
// Lenses for primitive types and other types that are not
|
|
// interesting to further focus.
|
|
public sealed class LeafLens<T, Whole> : ILens<T, Whole> {
|
|
public readonly System.Func<T, Whole> wrap;
|
|
public readonly T oldHole;
|
|
|
|
public LeafLens(System.Func<T, Whole> wrap, T oldHole) {
|
|
this.wrap = wrap;
|
|
this.oldHole = oldHole;
|
|
}
|
|
|
|
public Whole Update(Func<T, T> update) => wrap(update(oldHole));
|
|
}
|
|
|
|
public static class LensExtensionMethods {
|
|
public static Whole Update<Hole, Whole>(this ILens<Hole, Whole> lens, Hole newHole)
|
|
=> lens.Update(oldHole => newHole);
|
|
|
|
public static Whole Cons<T, Whole>(this ILens<ImmutableList<T>, Whole> lens, T value)
|
|
=> lens.Update(oldHole => oldHole.Cons(value));
|
|
|
|
public static ImmutableListLens<T, Whole>
|
|
ChainLens<T, Whole>(
|
|
this ImmutableList<T> hole,
|
|
System.Func<ImmutableList<T>, Whole> wrap)
|
|
=> new ImmutableListLens<T, Whole>(wrap: wrap, oldHole: hole);
|
|
|
|
public static ILens<string, Whole> ChainLens<Whole>(this string hole, System.Func<string, Whole> wrap) => new LeafLens<string, Whole>(wrap: wrap, oldHole: hole);
|
|
|
|
public static ILens<Func<GraphemeCluster,bool>, Whole> ChainLens<Whole>(this Func<GraphemeCluster,bool> hole, System.Func<Func<GraphemeCluster,bool>, Whole> wrap) => new LeafLens<Func<GraphemeCluster,bool>, Whole>(wrap: wrap, oldHole: hole);
|
|
|
|
public class FocusableLeaf<T> {
|
|
private readonly T value;
|
|
public FocusableLeaf(T value) { this.value = value; }
|
|
public LeafLens<T, Whole> ChainLens<Whole>(Func<T, Whole> wrap)
|
|
=> new LeafLens<T, Whole>(wrap: wrap, oldHole: value);
|
|
}
|
|
|
|
public static ILens<ImmutableList<string>, Whole> ChainLens<Whole>(this ImmutableList<string> hole, System.Func<ImmutableList<string>, Whole> wrap) => new ImmutableListLens<string, Whole>(wrap: wrap, oldHole: hole);
|
|
} |