Boxic DMN

Boxic DMN is a native Elixir loader, validator, and evaluator for Decision Model and Notation (DMN) 1.4 models. It uses boxic_feel for expression evaluation and does not require a JVM.

Installation

Add boxic_dmn to mix.exs:

def deps do
  [
    {:boxic_dmn, "~> 0.1.0"}
  ]
end

Quick start

Load XML explicitly, validate its normalized model, and evaluate a decision:

xml = """
<definitions id="example" name="Example" namespace="https://example.com/boxic">
  <decision id="greeting" name="Greeting">
    <literalExpression>
      <text>"Hello " + name</text>
    </literalExpression>
  </decision>
</definitions>
"""

with {:ok, model} <- Boxic.DMN.load_xml(xml),
     :ok <- Boxic.DMN.validate(model),
     {:ok, greeting} <- Boxic.DMN.evaluate(model, "Greeting", %{"name" => "Ada"}) do
  greeting
end

Use Boxic.DMN.load_file/1 for a filesystem path. It discovers sibling .dmn documents needed for namespace imports. The compatibility Boxic.DMN.load/1 function accepts either XML-looking input or a path, but the explicit functions provide clearer errors.

Loading returns {:ok, %Boxic.DMN.Model{}} or a documented load error. Validation returns :ok or {:error, errors}. Evaluation returns {:ok, value} or {:error, reason}.

Compatibility

Boxic targets DMN 1.4. Against the vendored official DMN Technology Compatibility Kit revision 0dbcaf9b98bc3af4e36d44a7aed95e9e85703a13, the DMN suite passes all 1,485 selected cases. This result covers the DMN suite; the separate FEEL suite is reported by boxic_feel.

Java external-function integration is intentionally not implemented because Boxic runs on the BEAM rather than the JVM. Trusted host functions can instead be exposed through Boxic.FEEL.ExternalFunctions.

External functions and trust

Pass an allowlisted external-function registry when evaluating:

Boxic.DMN.evaluate(model, "Price", inputs,
  external_functions: MyApp.DecisionFunctions
)

Registry entries execute application code in the evaluator process. Construct registries only from trusted application configuration, never from model content or untrusted strings. Applications should isolate or time-limit functions that perform remote or long-running work.

License

Boxic DMN is licensed under Apache-2.0. The official TCK corpus and local compatibility artifacts are not included in the Hex package.