RulesEngine - Define your business rules in boo DSL, Code in Flow Syntax

Rules engine allows you to define complex business rules in boo DSL as strings externally, outside of your source code, and execute them as part of your C# application. You can store rules in external text file / database, and change them without modifying your source code.

You can pass in any a POCO object as context to the rules and use it evaluate the rule. See example below.

Example:

Lets define rules on an Order class.

public class Order
{
    public double TotalPrice;
    public double Discount;
}

Your business rule can be if TotalPrice > 100, apply a discount of 10%. You can define both rule, and activity in boo DSL.

var businessRule = "return (this.TotalPrice > 100)";
var businessAction = @"this.Discount = 10; return true;";
var condition = new DslCondition { DslStatement = statement };
var rule = new ActivityRule(condition, new DslActivity
	{
		DslStatement = businessAction
	});
rule.Evaluate(order);

In above example, you can define business rule and actions externally in a file or database ( to track what rules executed on orders ). You can simply create an ActivityRule and pass condition and activity.

You can also create complex rules like:

var complexRule = (rule1 & rule2) | ( (rule3 | rule4) & (rule5 | rule6) );
complexRule.Evaluate(context);

Rules Engine is designed such that it can easily be extended to other DSL evaluators such as boo.

Rules Engine allows you to specify a Flow chart of your business requirement in easily understable syntax. The example below shows a sample flow. You can also use DSL conditions and activities as part of the flow. (The flow is a just a sample. It is not be a real business requirement :) ).

var flow = Flow.For<Order>()
            .Do(a => 
                a.Price = 10)
            .Then
            .Decide(o => o.Price > 10)
                .WhenTrue(a => a.Do(t => t.Price = 10)
                    .Then
                        .Decide(new DslCondition(condition))
                            .WhenTrue(b => b.Do(t => t.Price = 20))
                            .WhenFalse(b => b.Do(t => t.Price = 30))
                )
                .WhenFalse(a1 => a1.Do(t => t.Price = 30)
                    .Then.Do(new DslActivity(activity)).Then.Do(t => t.Price = 50).Then
                        .Decide(aa => aa.Price > 40).WhenFalse(a => a.Do(a2 => a2.Message ="test")));

var order = new Order { Price = 16 };
flow.Execute(order);