Compiling OpenSCENARIO 2.1 for Scenario-Based Testing in CARLA

TL;DR

This paper presents a novel compiler architecture that translates OpenSCENARIO 2.1 DSL directly into executable behaviors in CARLA, enabling scalable scenario-based testing with complex, concurrent actions.

Contribution

It introduces a multi-pass compiler pipeline with an ANTLR4 frontend and a custom runtime backend that maps OpenSCENARIO 2.1 directly to CARLA's API, improving integration and scalability.

Findings

Successfully compiles multi-actor scenarios with concurrent actions

Demonstrates dynamic mathematical expressions and asynchronous signaling handling

Establishes a baseline for reproducible large-scale scenario testing

Abstract

While the ASAM OpenSCENARIO 2.1 Domain-Specific Language (DSL) enables declarative, intent-driven authoring for Scenario-Based Testing (SBT), its integration into open-source simulators like CARLA remains limited by legacy parsers. We propose a multi-pass modern compiler architecture that translates the OpenSCENARIO 2.1 DSL directly into executable CARLA behaviors. The pipeline features an ANTLR4 frontend for Abstract Syntax Tree (AST) generation, a semantic middle-end, and a runtime backend that synthesizes deterministic py_trees behavior trees. Mapping the standardized domain ontology directly to CARLA's procedural API via a custom method registry eliminates the need for external logic solvers. A demonstrative multi-actor cut-in and evasive maneuver, selected from a wider suite of validated scenarios, confirms the compiler's ability to process concurrent actions, dynamic mathematical expressions, and asynchronous signaling. This framework establishes a functional baseline for reproducible, large-scale SBT, paving the way for future C++ optimizations to mitigate current Python-based computational overhead.