Hyperbee.Expressions 1.0.0-develop.241104201905

Welcome to Hyperbee Expressions

Hyperbee.Expressions is a library for creating c# expression trees that extend the capabilities of standard expression trees to handle asynchronous workflows and other language constructs.

Features

• Async Expressions

  • AwaitExpression: An expression that represents an await operation.
  • AsyncBlockExpression: An expression that represents an asynchronous code block.

• Using Expression

  • UsingExpression: An expression that automatically disposes IDisposable resources.

• Looping Expressions

  • WhileExpression: An expression that represents a while loop.
  • ForExpression: An expression that represents a for loop.
  • ForEachExpression: An expression that represents a foreach loop.

• Supports Fast Expression Compiler (FEC) for improved performance.

Examples

Asynchronous Expressions

The following example demonstrates how to create an asynchronous expression tree.

When the expression tree is compiled, the BlockAsyncExpression will auto-generate a state machine that executes AwaitExpressions in the block asynchronously.

the `BlockAsync` expression will generate a state machine that executes the expressions in the block asynchronously.

```csharp

public class AsyncExample
{
    public async Task ExampleAsync()
    {
        // Variables to store the results
        var result1 = Expression.Variable( typeof(int), "result1" );
        var result2 = Expression.Variable( typeof(int), "result2" );

        // Define two async method calls

        var instance = Expression.Constant( this );

        var awaitExpr1 = ExpressionExtensions.Await( 
            Expression.Call( instance, nameof(FirstAsyncMethod), Type.EmptyTypes ) 
        );

        var awaitExpr2 = ExpressionExtensions.Await( 
            Expression.Call( instance, nameof(SecondAsyncMethod), Type.EmptyTypes, result1 )
        );

        // Assign the results of the await
        var assignResult1 = Expression.Assign( result1, awaitExpr1 );
        var assignResult2 = Expression.Assign( result2, awaitExpr2 );

        // Create an async block that calls both methods and assigns their results
        var asyncBlock = AsyncExpression.BlockAsync(
            [result1, result2],
            assignResult1,
            assignResult2
        );

        // Compile and execute the async block
        var lambda = Expression.Lambda<Func<Task<int>>>( asyncBlock );
        var compiledLambda = lambda.Compile();
        var resultValue2 = await compiledLambda();

        Console.WriteLine( $"Second async method result: {resultValue2}" );
    }

    public static async Task<int> FirstAsyncMethod()
    {
        await Task.Delay( 1000 ); // Simulate async work
        return 42; // Example result
    }

    public static async Task<int> SecondAsyncMethod( int value )
    {
        await Task.Delay( 1000 ); // Simulate async work
        return value * 2; // Example result
    }
}

Using Expression

The following example demonstrates how to create a Using expression.

public class UsingExample
{
    private class DisposableResource : IDisposable
    {
        public bool IsDisposed { get; private set; }
        public void Dispose() => IsDisposed = true;
    }

    public void UsingExpression_ShouldDisposeResource_AfterUse()
    {
        var resource = new TestDisposableResource();

        var disposableExpression = Expression.Constant( resource, typeof( TestDisposableResource ) );
        var bodyExpression = Expression.Empty(); // Actual body isn't important

        var usingExpression = ExpressionExtensions.Using( 
            disposableExpression, 
            bodyExpression 
        );

        var compiledLambda = Expression.Lambda<Action>( reducedExpression ).Compile();

        compiledLambda();

        Console.WriteLine( $"Resource was disposed {resource.IsDisposed}." );
    }
}

Credits

Special thanks to:

• Sergey Tepliakov - Dissecting the async methods in C#.
• Fast Expression Compiler for improved performance.
• Just The Docs for the documentation theme.

Contributing

We welcome contributions! Please see our Contributing Guide for more details.