• Abstraction Layer (introduced by GoF) - high level control layer, that only defines what has to be done, but leaves the actual implementation to the implementation layer
• Implementation Layer (introduced by GoF) - low level layer, that implements what’s needed, defined by the abstraction layer
• A domain-specific language (DSL) is a computer language specialized to a particular application domain. Simpler DSLs, particularly ones used by a single application, are sometimes informally called mini-languages.