DEFINING EXTENSIBLE EXPRESSION BEHAVIOR IN A RULES SYSTEM

Described herein is technology for, among other things, enabling use of custom expressions in a rules engine. The rules engine may be used in conjunction with a workflow. The technology involves providing a custom expression with access to validation context and execution context of the workflow. The custom expression can then participate in rules engine validation and execution. Furthermore, the technology allows for variables of the custom expression to be analyzed so that the rules engine can discover the variable dependencies of the custom expression and any side effects that drive forward chaining.