MASL is a Shlaer-Mellor model and action specification language that can textually represent the executable elements of Object-Oriented Analysis models. This article introduced a model of MASL: an *OOA of MASL*, or metamodel of the modeling language.
The OOA of MASL is semantically equivalent to the xtUML metamodel, OOA of OOA. However, because the two languages were modeled independently, their metamodels are not identical.
The original article compared statistics across the subsystems of the two metamodels. Those comparisons showed that the MASL action language provided substantially richer support for expressions than the Value subsystem of xtUML.
Subsystem statistics from the original article.
The [OOA of MASL source model](https://github.com/xtuml/mc/tree/master/model/ooamasl) is available in the xtuml/mc repository.
*Historical note: this article was published in January 2020. Repository contents and language tooling may have evolved since then.*
