That said - working with data is an area that lends itself well to visual programming. Data pipelines don’t have branching control flow and So you’ll see some really successful companies in this space.
Alteryx has a $8b market cap. Excel is visual programming as well.
One type of control structure I have not seen a good implementation of is pattern matching. But that doesn't mean it can't exist, and it's also something most text-based languages don't do anyway.
Not quite. You'd need to draw two parallel boxes, each of which is strictly single-entry/single-exit, and draw a while loop in each box. This is because a while loop
Now, the two while loops, as shown here, have no dependencies between each other and are indeed processing in parallel. However, there are various mechanisms in LabVIEW to exchange data between the two loops, the most common being queues, in which case they process concurrently.
You can also have a for loop iterating on an array.
In LabVIEW, it's nice because it's trivial to configure the loop iterations to occur in parallel (if there are no dependencies between iterations), using all available cores in the computer.
And by pattern matching I meant something like the pattern matching and type destructuring you find in SML, Ocaml, F#, and Elixir.
--> [A] --> [B] --> ------>
Either of these is a consistent choice in itself, but they don't play well together as part of the same diagram unless rigorously separated.
A different point is that some high-level abstractions do have a fairly natural visual representation. This even includes the "functors" and "monads" that are well-known in FP. In general, one should not be surprised if category-theoretical abstractions turn out to be representable in this way. (Many visual languages actually turn this into a source of confusion, by conflating operations on an atomic piece of data with operations on a stream or sequence of singular data points. A stream is a kind of functor, which is why it (with its peculiar operations) is endowed with a simple representation in dataflow. But there are other functors of interest.)