Boxed Expressions

Boxed Expressions are a standard way to visualize and edit decision logic in DMN. They provide a structured, graphical representation of logic that maps directly to FEEL expressions.

Introduction

In DMN, every decision node has an associated expression that determines its value. Boxed expressions decompose this logic into nested "boxes," making complex logic easier to understand and maintain than a single long text expression.

Types of Expressions

The platform supports all standard DMN boxed expressions:

Literal Expression

The simplest form of logic. A single block of text containing a FEEL expression (e.g., a formula or a variable reference).

Decision Table

A tabular representation of conditional logic. It maps a set of inputs to outputs based on defined rules. This is the most common expression type.

Context

A list of key-value pairs. Each entry has a name and an expression. It is similar to defining a local object or a set of variables.

List

An ordered collection of items. Each item in the list is itself an expression.

Relation

A table of data where each row represents an entity and columns represent attributes. It acts like a static database table.

Function Definition

Defines a reusable piece of logic with parameters. Boxed functions can be standard FEEL expressions or use external logic.

Invocation

Calls a defined function (Business Knowledge Model) with specific arguments.

Nesting

A key feature of boxed expressions is nesting. A Context entry can contain a Decision Table, which in turn can contain a List, and so on. This allows you to model arbitrarily complex logic in a structured way.