[1] OCL may now be used with any Meta-Object Facility (MOF) Object Management Group (OMG) meta-model, including UML.
OCL is a key component of the new OMG standard recommendation for transforming models, the Queries/Views/Transformations (QVT) specification.
OCL makes a Meta-Object Facility model more precise by associating assertions with its meta-elements.
Several model transformation languages like GReAT, VIATRA, or Tefkat are presently available, with different levels of compliance with the QVT standard.
[6] These extensions are consistent with the map and function types present in modern programming languages such as Python and Swift.