The Embedded Constraint Language: A Transformation Language for Visual Models

Domain-specific modeling (DSM) assists in the creation of visual modeling environments that match the intentions and abstractions of a specific class of end-users. As stepwise refinement is applied, the models may undergo a series of structural and behavioral transformations. The Embedded Constraint Language (ECL) is a textual language for describing transformations on visual models. In a manner similar to the Object Constraint Language (OCL), the ECL provides features such as collection and model navigation. The ECL also provides a rich set of operators that are not found in the OCL in order to support model aggregations, connections and transformations. Over the past four years, the ECL has evolved into a powerful transformation language that supports a procedural style of specification. The language and its associated model transformation engine (called C-SAW) have mature tool support and have been applied to various large models, particularly in the embedded avionics domain. The paper presents the ECL language features, as well as an example application.