I'm very interested in dataflow and concurrency focused languages. I've read up on the subject and repeatedly I see SIGNAL, Esterel, and Lustre mentioned; so I take it they're prominent players in those fields. However, many of their links in the resources I found are dead and they don't seem very accessible. I managed to find a couple compilers I can compile from source (Polychrony Toolset for SIGNAL and the Columbia Compiler for Esterel) but they've both had issues when trying to compile with cmake. Even textbooks teaching these languages have been tough to come by.
With the background of the way, my actual questions are: is anyone really familiar with this field of programming? Are these languages still big deals, or have they "died out" by now? Could it be they're just available to big companies with a hefty price tag, so the average programmer wouldn't really be able to pick those languages up?
I ran into a couple other dataflow/concurrent paradigm languages, such as Oz or E, but they seemed to be mostly for education and not suitable for real world projects. Not to say they aren't impressive languages, but their implementation was limited and it would be unlikely to see them in production contexts. Does anyone know of other languages in this field they can recommend that are actually accessible (have good documentation, tutorials, and an installable compiler to actually code in)? Or can anyone clarify a language such as Oz or E and hopefully show that they indeed are good enough for large real world projects?
All the languages you mentioned are not widespread. This means their compilers and runtime have bugs, the community is narrow and can give little help, and linking with general purpose libraries can be problematic.
I recommend to use an actively supported general purpose language such as Java, Scala, Kotlin or C++. They all have libraries to support asynchronous computations, and dataflow is no more than support of asynchronous procedure call. You even can develop your own dataflow library. This is not that hard: I wrote a dataflow library for Java which is only 40 kilobytes of source code.