c# snippets

IndicesAndRanges.csx

// https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/proposals/csharp-8.0/ranges

#region Indexable Example
//System.Index
// use '^' operator: means read from end = true
// '^' operator requires type is countable and have indexer:

interface IIndexable<T>{
    public int Length { get; } // need public property 'Length', which has get access 
    public T this[int index] { get; } // need public indexer, which takes a single int as the argument.
    
    //or need public indexer, which has parameter type of System.Index
    // public T this[Index index] { get; } 
}

class X : IIndexable<string>
{
    private int _length = 10;
    public int Length{
        get => _length;
    }

     public string this[int index] => "asd";

}

var x = new X();
Console.WriteLine(x[^1]);

#endregion

#region Rangeable example
//System.Range
// use range operator x..y. It is a binary infix operator that accepts two expressions
// '..' operator requires type is countable and has slice method
// for range operator x..y, x is included and y is excluded. .. means all, y can be applied with hat operator '^' 


public interface IRangeable<T>{
    public int Length { get; } // need public property 'Length', which has get access 

    public IRangeable<T> Slice(int start, int end);// need public member Slice, which takes two int as argument

    // or need public indexer, which has parameter type of System.Range
    // public T this[Range range] { get; }
}

public class Y : IRangeable<string>{
    public int Length{ get => 10; }
    public IRangeable<string> Slice(int start, int end){
        return new Y();
    }
}

var y = new Y();
var result = y[..];
#endregion

/*
 * could use range operator replace String.Substring() method 
 */