The Roles of Symmetry And Orthogonality In Design - Charley Bay - CppCon 2021

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An essential aspect in designing C and C++ systems is to validate the execution flow and resource contention of a proposed approach in the contexts of symmetry and orthogonality.
The role of symmetry is to provide some level of notional understanding without requiring direct inspection (using “similarity” to enable greater scaling and management of design complexity). The role of orthogonality is to remove edge cases and coupling by making things unrelated (thereby making whole system scaling to be simpler, more efficient, and more adaptable).
These roles establish symmetry and orthogonality as useful tools to define our systems by leveraging different aspects of “knowing” many things about our system components and their possible interactions intuitively, and without tedious scrutiny. Symmetry allows us to “know” things we should not otherwise know; while orthogonality grants simplicity to dismiss as a possibility some behaviors or component interactions within the resulting system.
In practice, we use C and C++ language guarantees to implement design choices. But, these design choices come from integrating: (1) the problem to be addressed; and (2) exploiting symmetry and orthogonality to fabricate a system that is logical, implementable, scalable, and unsurprising.
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Charley Bay
Charley is a software developer with over three decades of experience using C++ in multiple regulated and high-performance fields focused on large-scale and distributed systems in performance-sensitive environments including time-sensitive processing of large data sets, performance visualization, real-time processing, low-latency, embedded, and system status and control.
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[@alexandergraf2505]

Thanks for this awesome talk! While dealing with a very abstract idea, the message is crystal clear and applicable to so many problems. I will watch out for signs of orthogonality and symmetry in all my future design decissions. It is so difficult to reason about good design and taste. I really feel these concepts help to make solid arguments.

[@kodirovsshik]

0:23 I just like it Thank you for an interesting talk btw

[@bunpasi]

It's pretty funny that this talk has the most chaotic slides I've ever seen. The presentation (with the owls) was great though. The C++ Core Guideline P.2 states that you should write in standard C++ and that you can isolate variations. If asymmetry is really required, you can encapsulate it to hide it from the interface.

[@Omnifarious0]

Orthogonality is a form of symmetry. Symmetry is not just balance. It also means that some property remains independent of certain kinds of change. This a fundamental equivalence. Conservation of energy is exactly equivalent to time symmetry. Conservation of linear momentum is exactly equivalent to translation symmetry.

[@PrzemyslawSliwinski]

24:25 - plastic garbage in oceans shows how difficult is to maintain the said symmetry in real distributed systems (even though we have an implicit move semantics)... ;)

[@heater5979]

Is there any symmetry and orthogonality in the C++ language?

[@bakedbeings]

Templated classes and functions add orthogonality, as do operator and function overrides. The algorithms and ranges libraries aim to treat a range of different container classes the same way, also orthogonal 👍