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6.3. Supported Concepts
Table 6.3.: Concepts Supported by the OMOP: Supported by OMOP (X), Partial Support
by OMOP (+)
Supported Sem OMOP Supported Sem OMOP
Active Objects X X No-Intercession X X
Actors X X Side-Effect Free X X
Asynchronous Invocation X X Transactions X X
Axum-Domains X X Vats X X
Isolation X X
Partial Support Sem OMOP Partial Support Sem OMOP
By-Value X + Persistent Data Structures X +
Channels X + Replication X +
Data Streams X + Speculative Execution X +
Map/Reduce X + Tuple Spaces X +
Message sends X +
referred to most of them, and thus, this section discusses them only briefly.
The structure of the discussion roughly mirrors the structure of Sec. 3.2.2.
Asynchronous Invocation, Active Objects Active objects and other concepts
that rely on the guarantee that an object’s methods are invoked asynchronously
are directly supported by the OMOP. The provided intercession
handler #requestExecOf:on:with:lkup: can be used to customize invocation
constraints. As previously discussed in Sec. 6.2.1, intercession handlers can be
used for instance to implement Clojure agents. Its flexibility enables the implementation
of a wide range of different policies and asynchronous invocation
is one of them.
Actors, Axum-Domains, Isolation, Vats The required support for proper
state encapsulation, i. e., isolation, can be realized by combining support for
ownership, intercession handlers for reading and writing of object fields and
globals, as well as intercession handlers for primitives. By customizing these,
as demonstrated in Sec. 6.2.3, it becomes possible to support concurrent programming
concepts such as actors, axum-domains, and vats.
No-intercession, Side-effect Freedom The notion of disallowing intercession,
i. e., reflective operations is often used to increase control over state
changes. Similarly, the requirement of some concepts that operations be sideeffect
free stems from the desire to simplify reasoning over code. Both no-
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