The evaluation engine provides an infrastructure for decoupled evaluation. Features: * The evaluation engine provides a single entry point to ask questions (queries, calculations, ...) * Questioner is completely decoupled from answer finding algorithm. * Hierarchical evaluation engines (children inherit knowledge from parent) * Solution definitions can be loaded from modules or plug-ins. * Extensible to solve any kind of question (validation rules, status queries, …) * Fluent definition syntax allowing constraints, strategies, aggregators and multiple expressions per question. * Thorough customizable logging. bbv.Common.EvaluationEngine is a part of bbv.Common, a library of .NET components and functionality including: * (a)synchronous notification component with thread switching using publisher-subscriber pattern, * hierarchical state machine with fluent definition syntax, * programmatic, loosely coupled, context based rule engine, * support for active objects to build multi-threaded applications