reactive/Ix.NET/Source/System.Linq.Async/System/Linq/Operators/Sum.Generated.tt

<#@ template debug="false" hostspecific="false" language="C#" #>
<#@ assembly name="System.Core" #>
<#@ import namespace="System.Linq" #>
<#@ import namespace="System.Text" #>
<#@ import namespace="System.Collections.Generic" #>
<#@ output extension=".cs" #>
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT License.
// See the LICENSE file in the project root for more information. 

using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;

namespace System.Linq
{
    public static partial class AsyncEnumerable
    {
<#
var os = new[]
{
    new { type = "int", zero = "0", @checked = true },
    new { type = "long", zero = "0L", @checked = true },
    new { type = "float", zero = "0.0f", @checked = false },
    new { type = "double", zero = "0.0", @checked = false },
    new { type = "decimal", zero = "0m", @checked = false },
    new { type = "int?", zero = "0", @checked = true },
    new { type = "long?", zero = "0L", @checked = true },
    new { type = "float?", zero = "0.0f", @checked = false },
    new { type = "double?", zero = "0.0", @checked = false },
    new { type = "decimal?", zero = "0m", @checked = false },
};

foreach (var o in os)
{
    var n = o.type.EndsWith("?") ? ".GetValueOrDefault()" : "";

    var typeStr = o.type;
    if (o.type.EndsWith("?")) {
        typeStr = "Nullable{" + o.type.Substring(0, 1).ToUpper() + o.type.Substring(1, o.type.Length - 2) + "}";
    }
#>
        /// <summary>
        /// Computes the sum of a sequence of <see cref="<#=typeStr#>" /> values.
        /// </summary>
        /// <param name="source">A sequence of <see cref="<#=typeStr#>" /> values to calculate the sum of.</param>
        /// <param name="cancellationToken">The optional cancellation token to be used for cancelling the sequence at any time.</param>
        /// <returns>An async-enumerable sequence containing a single element with the sum of the values in the source sequence.</returns>
        /// <exception cref="ArgumentNullException"><paramref name="source"/> is null.</exception>
        /// <remarks>The return type of this operator differs from the corresponding operator on IEnumerable in order to retain asynchronous behavior.</remarks>
        public static ValueTask<<#=o.type#>> SumAsync(this IAsyncEnumerable<<#=o.type#>> source, CancellationToken cancellationToken = default)
        {
            if (source == null)
                throw Error.ArgumentNull(nameof(source));

            return Core(source, cancellationToken);

            static async ValueTask<<#=o.type#>> Core(IAsyncEnumerable<<#=o.type#>> source, CancellationToken cancellationToken)
            {
                var sum = <#=o.zero#>;

                await foreach (<#=o.type#> value in source.WithCancellation(cancellationToken).ConfigureAwait(false))
                {
<#
if (o.@checked)
{
#>
                    checked
                    {
                        sum += value<#=n#>;
                    }
<#
}
else
{
#>
                    sum += value<#=n#>;
<#
}
#>
                }

                return sum;
            }
        }

        /// <summary>
        /// Computes the sum of a sequence of <see cref="<#=typeStr#>" /> values that are obtained by invoking a transform function on each element of the input sequence.
        /// </summary>
        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
        /// <param name="source">A sequence of values that are used to calculate a sum.</param>
        /// <param name="selector">A transform function to apply to each element.</param>
        /// <param name="cancellationToken">The optional cancellation token to be used for cancelling the sequence at any time.</param>
        /// <returns>An async-enumerable sequence containing a single element with the sum of the values in the source sequence.</returns>
        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="selector"/> is null.</exception>
        /// <remarks>The return type of this operator differs from the corresponding operator on IEnumerable in order to retain asynchronous behavior.</remarks>
        public static ValueTask<<#=o.type#>> SumAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, <#=o.type#>> selector, CancellationToken cancellationToken = default)
        {
            if (source == null)
                throw Error.ArgumentNull(nameof(source));
            if (selector == null)
                throw Error.ArgumentNull(nameof(selector));

            return Core(source, selector, cancellationToken);

            static async ValueTask<<#=o.type#>> Core(IAsyncEnumerable<TSource> source, Func<TSource, <#=o.type#>> selector, CancellationToken cancellationToken)
            {
                var sum = <#=o.zero#>;

                await foreach (TSource item in source.WithCancellation(cancellationToken).ConfigureAwait(false))
                {
                    var value = selector(item);

<#
if (o.@checked)
{
#>
                    checked
                    {
                        sum += value<#=n#>;
                    }
<#
}
else
{
#>
                    sum += value<#=n#>;
<#
}
#>
                }

                return sum;
            }
        }

        internal static ValueTask<<#=o.type#>> SumAwaitAsyncCore<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, ValueTask<<#=o.type#>>> selector, CancellationToken cancellationToken = default)
        {
            if (source == null)
                throw Error.ArgumentNull(nameof(source));
            if (selector == null)
                throw Error.ArgumentNull(nameof(selector));

            return Core(source, selector, cancellationToken);

            static async ValueTask<<#=o.type#>> Core(IAsyncEnumerable<TSource> source, Func<TSource, ValueTask<<#=o.type#>>> selector, CancellationToken cancellationToken)
            {
                var sum = <#=o.zero#>;

                await foreach (TSource item in source.WithCancellation(cancellationToken).ConfigureAwait(false))
                {
                    var value = await selector(item).ConfigureAwait(false);

<#
if (o.@checked)
{
#>
                    checked
                    {
                        sum += value<#=n#>;
                    }
<#
}
else
{
#>
                    sum += value<#=n#>;
<#
}
#>
                }

                return sum;
            }
        }

#if !NO_DEEP_CANCELLATION
        internal static ValueTask<<#=o.type#>> SumAwaitWithCancellationAsyncCore<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, ValueTask<<#=o.type#>>> selector, CancellationToken cancellationToken = default)
        {
            if (source == null)
                throw Error.ArgumentNull(nameof(source));
            if (selector == null)
                throw Error.ArgumentNull(nameof(selector));

            return Core(source, selector, cancellationToken);

            static async ValueTask<<#=o.type#>> Core(IAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, ValueTask<<#=o.type#>>> selector, CancellationToken cancellationToken)
            {
                var sum = <#=o.zero#>;

                await foreach (TSource item in source.WithCancellation(cancellationToken).ConfigureAwait(false))
                {
                    var value = await selector(item, cancellationToken).ConfigureAwait(false);

<#
if (o.@checked)
{
#>
                    checked
                    {
                        sum += value<#=n#>;
                    }
<#
}
else
{
#>
                    sum += value<#=n#>;
<#
}
#>
                }

                return sum;
            }
        }
#endif

<#
}
#>
    }
}