Classification of the Principal Programming Paradigms (2009)

I find this diagram less easy to navigate than the simpler categorization of declarative vs imperative with four subcategories:

I.e. Imperative: Procedural, Object-oriented

Declarative: Functional, Logic (or better term for Prolog-esque languages - constraint-based perhaps)

Four simple categories with two meta categories.

As far as I remember one of the main ideas was "dataflow variables", which are lazily evaluated in parallel (?)

I've read about this paradigm in the literature, e.g. with the Lucid language and others. And the book goes into some depth about it.

But somehow this paradigm hasn't caught on, despite the constant production of new experimental languages. And I've never seen a real program in it -- e.g. one over 5K lines that people use.

Anyone have a conjecture on what happened? Is it flawed, or did nobody pay enough attention? I think there is some overlap with async/await which seems to be the dominant concurrency paradigm now (C#, JS, Python, Rust, etc.)

I think one issue is that real systems are composed of multiple languages, and it's hard to bridge programs with wildly different evaluation semantics with C or JavaScript code.

And I guess the paradigm is not "reactive". It wants to control the main loop, but in GUIs and networking code where async/await is appropriate, the app doesn't "own" the thread of control. A new paradigm for batch programs is perhaps of limited use.

I guess I sort of answered my own question -- the model doesn't solve enough problems to justify its cost. (Also, another issue is that it's a model of very fine-grained parallelism, where as coarse-grained parallelism with limited communication is faster. That's how people optimize in practice.)

I'm interested in any contrary opinions though.

By the taxonomy of the diagram, pure APL-style array programming is just first-order functional programming. Real array programming languages also introduce features from other branches of the tree (especially imperative programming and closures), of course. I don't think this diagram is supposed to be a clear-cut categorisation of languages, but more of a rough map of idealised paradigms. By the standards of this diagram, most languages are multi-paradigm.

The chart is not by language. There are just some languages for example because there are many languages for a single paradigm

The article is named for “dummies” but it should be noted that it is much more difficult to read than other for dummies materials.