Func

Func<From,To> service request is handled and internally processed as ConverterRequest.

// Create dependency injection
IServiceProvider serviceProvider = Services.Create(ConverterHandlers.Instance);
// Query converter
Func<double, BigInteger> converter = serviceProvider.GetRequiredService<Func<double, BigInteger>>();
// Convert
BigInteger b = converter(2.0);

Func<From, IServiceProvider, To> is version where argument can be provided to IWriter.

// Create dependency injection
IServiceProvider serviceProvider = Services.Create(ConverterHandlers.Instance);
// Query converter
Func<string, IServiceProvider, DateTime> parser = serviceProvider.GetRequiredService<Func<string, IServiceProvider, DateTime>>();
// Parse
var dateFormat = new Avalanche.Converter.StringConverter.FormatArgument(CultureInfo.InvariantCulture, "yyyyMMdd_HHmmss");
DateTime dateTime = parser("20200505_101010", dateFormat);

TryWriteToRef<From, To> is another delegate that can be requested. It uses TryWrite.

// Create dependency injection
IServiceProvider serviceProvider = Services.Create(ConverterHandlers.Instance);
// Query converter
TryWriteToRef<string, DateTime> parser = serviceProvider.GetRequiredService<TryWriteToRef<string, DateTime>>();
// Convert
var dateFormat = new Avalanche.Converter.StringConverter.FormatArgument(CultureInfo.InvariantCulture, "yyyyMMdd_HHmmss");
DateTime dateTime = default;
bool ok = parser("20200505_101010", ref dateTime, dateFormat);

Converters can be added creating a IHandler that process ConverterRequests. The following example builds converters that concatenate elements into a string.

// Create dependency injection
IServiceProvider serviceProvider = Services.Create((ConverterHandlers.Instance, new EnumerableJoinConverterFactory()));

// Request printer
Func<HashSet<DateTime>, string> dateTimeSetPrinter = serviceProvider.GetRequiredService<Func<HashSet<DateTime>, string>>();
// Create set
HashSet<DateTime> times = new HashSet<DateTime>
{
    new DateTime(1999, 1, 1),
    new DateTime(2003, 2, 2),
    new DateTime(2005, 5, 5),
};
// Print
string print = dateTimeSetPrinter(times);
Console.WriteLine(print);
// "1.1.1999 0.00.00, 2.2.2003 0.00.00, 5.5.2005 0.00.00"

/// <summary>Creates writers that concatenate elements and outputs as string.</summary>
public class EnumerableJoinConverterFactory : IHandler<ConverterRequest, IWriter>
{
    [Order(-1_000_000_000_000L)] // <- Make sure order is BEFORE StringConverterFactory
    public void Handle(IQuery<ConverterRequest, IWriter> query)
    {
        // Already handled
        if (query.Handled()) return;
        // Cast types
        if (query.Request.From is not Type fromType || query.Request.To is not Type toType) return;
        // Expect 'to' as string
        if (!toType.Equals(typeof(string))) return;
        // Expect 'from' as IEnumerable<T>
        if (!TypeUtilities.TryGetTypeArgumentOfCorrespondingDefinedType(fromType, typeof(IEnumerable<>), 0, out Type elementType)) return;
        // Query element printer
        var elementCastRequest = new ConverterRequest(elementType, typeof(string));
        if (!query.Service.TryGet(elementCastRequest, out IWriterTo<string> elementPrinter)) return;
        // Create writer
        IWriter writer = ctor.Create(fromType, elementType, elementPrinter);
        // Assign result
        query.Response.SetValue(writer);
    }

    static ConstructorT2<IWriter, IWriter> ctor = new ConstructorT2<IWriter, IWriter>(typeof(EnumerableJoinWriter<,>));

    /// <summary>Writer that concatenates element and prints as string. Uses ", " as separator.</summary>
    /// <typeparam name="E">Enumerable type</typeparam>
    /// <typeparam name="T">Element type</typeparam>
    class EnumerableJoinWriter<E, T> : WriterToRefCastObject<E, string>.FromObject where E : IEnumerable<T>
    {
        IWriterToRef<T, string> elementPrinter;

        public EnumerableJoinWriter(IWriter elementPrinter)
        {
            this.elementPrinter = (IWriterToRef<T, string>)elementPrinter;
        }

        public override bool TryWrite(E from, ref string to, IServiceProvider context = null)
        {
            if (from == null) return false;
            StringBuilder sb = new StringBuilder();
            foreach (T element in from)
            {
                if (sb.Length > 0) sb.Append(", ");
                if (elementPrinter.TryRead(element, out string print, context)) sb.Append(print);
            }
            to = sb.ToString();
            return true;
        }
    }
}

Requesting same converter as Func<From, IServiceProvider, To> allows to feed date-time formats.

// Request printer where format can be supplied
Func<HashSet<DateTime>, IServiceProvider, string> dateTimeSetPrinter2 = serviceProvider.GetRequiredService<Func<HashSet<DateTime>, IServiceProvider, string>>();
// Create format
var dateFormat = new Avalanche.Converter.StringConverter.FormatArgument(CultureInfo.InvariantCulture, "yyyyMMdd_HHmmss");
// Print
string print2 = dateTimeSetPrinter2(times, dateFormat);
Console.WriteLine(print2);
// 19990101_000000, 20030202_000000, 20050505_000000

Full Example

Full example

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Numerics;
using System.Text;
using Avalanche.Converter;
using Avalanche.Service;
using Avalanche.Utilities;
using Avalanche.Writer;
using Microsoft.Extensions.DependencyInjection;

public class func
{
    public static void Run()
    {
        {
            // <01>
            // Create dependency injection
            IServiceProvider serviceProvider = Services.Create(ConverterHandlers.Instance);
            // Query converter
            Func<double, BigInteger> converter = serviceProvider.GetRequiredService<Func<double, BigInteger>>();
            // Convert
            BigInteger b = converter(2.0);
            // </01>
        }
        {
            // <02>
            // Create dependency injection
            IServiceProvider serviceProvider = Services.Create(ConverterHandlers.Instance);
            // Query converter
            Func<string, IServiceProvider, DateTime> parser = serviceProvider.GetRequiredService<Func<string, IServiceProvider, DateTime>>();
            // Parse
            var dateFormat = new Avalanche.Converter.StringConverter.FormatArgument(CultureInfo.InvariantCulture, "yyyyMMdd_HHmmss");
            DateTime dateTime = parser("20200505_101010", dateFormat);
            // </02>
        }
        {
            // <03>
            // Create dependency injection
            IServiceProvider serviceProvider = Services.Create(ConverterHandlers.Instance);
            // Query converter
            TryWriteToRef<string, DateTime> parser = serviceProvider.GetRequiredService<TryWriteToRef<string, DateTime>>();
            // Convert
            var dateFormat = new Avalanche.Converter.StringConverter.FormatArgument(CultureInfo.InvariantCulture, "yyyyMMdd_HHmmss");
            DateTime dateTime = default;
            bool ok = parser("20200505_101010", ref dateTime, dateFormat);
            // </03>
        }
        {
            // <04>
            // Create dependency injection
            IServiceProvider serviceProvider = Services.Create((ConverterHandlers.Instance, new EnumerableJoinConverterFactory()));

            // Request printer
            Func<HashSet<DateTime>, string> dateTimeSetPrinter = serviceProvider.GetRequiredService<Func<HashSet<DateTime>, string>>();
            // Create set
            HashSet<DateTime> times = new HashSet<DateTime>
            {
                new DateTime(1999, 1, 1),
                new DateTime(2003, 2, 2),
                new DateTime(2005, 5, 5),
            };
            // Print
            string print = dateTimeSetPrinter(times);
            Console.WriteLine(print);
            // "1.1.1999 0.00.00, 2.2.2003 0.00.00, 5.5.2005 0.00.00"
            // </04>
            // <05>
            // Request printer where format can be supplied
            Func<HashSet<DateTime>, IServiceProvider, string> dateTimeSetPrinter2 = serviceProvider.GetRequiredService<Func<HashSet<DateTime>, IServiceProvider, string>>();
            // Create format
            var dateFormat = new Avalanche.Converter.StringConverter.FormatArgument(CultureInfo.InvariantCulture, "yyyyMMdd_HHmmss");
            // Print
            string print2 = dateTimeSetPrinter2(times, dateFormat);
            Console.WriteLine(print2);
            // 19990101_000000, 20030202_000000, 20050505_000000
            // </05>
        }
    }
}

// <10>
/// <summary>Creates writers that concatenate elements and outputs as string.</summary>
public class EnumerableJoinConverterFactory : IHandler<ConverterRequest, IWriter>
{
    [Order(-1_000_000_000_000L)] // <- Make sure order is BEFORE StringConverterFactory
    public void Handle(IQuery<ConverterRequest, IWriter> query)
    {
        // Already handled
        if (query.Handled()) return;
        // Cast types
        if (query.Request.From is not Type fromType || query.Request.To is not Type toType) return;
        // Expect 'to' as string
        if (!toType.Equals(typeof(string))) return;
        // Expect 'from' as IEnumerable<T>
        if (!TypeUtilities.TryGetTypeArgumentOfCorrespondingDefinedType(fromType, typeof(IEnumerable<>), 0, out Type elementType)) return;
        // Query element printer
        var elementCastRequest = new ConverterRequest(elementType, typeof(string));
        if (!query.Service.TryGet(elementCastRequest, out IWriterTo<string> elementPrinter)) return;
        // Create writer
        IWriter writer = ctor.Create(fromType, elementType, elementPrinter);
        // Assign result
        query.Response.SetValue(writer);
    }

    static ConstructorT2<IWriter, IWriter> ctor = new ConstructorT2<IWriter, IWriter>(typeof(EnumerableJoinWriter<,>));

    /// <summary>Writer that concatenates element and prints as string. Uses ", " as separator.</summary>
    /// <typeparam name="E">Enumerable type</typeparam>
    /// <typeparam name="T">Element type</typeparam>
    class EnumerableJoinWriter<E, T> : WriterToRefCastObject<E, string>.FromObject where E : IEnumerable<T>
    {
        IWriterToRef<T, string> elementPrinter;

        public EnumerableJoinWriter(IWriter elementPrinter)
        {
            this.elementPrinter = (IWriterToRef<T, string>)elementPrinter;
        }

        public override bool TryWrite(E from, ref string to, IServiceProvider context = null)
        {
            if (from == null) return false;
            StringBuilder sb = new StringBuilder();
            foreach (T element in from)
            {
                if (sb.Length > 0) sb.Append(", ");
                if (elementPrinter.TryRead(element, out string print, context)) sb.Append(print);
            }
            to = sb.ToString();
            return true;
        }
    }
}
// </10>