Wow, completely the opposite experience here. The majority of the prog. lang. enthusiasts I know are deeply into other aspects of computer science. They love high level languages because they can express their ideas so cleanly. Lots of devs are drooling over Rust because it allows us clean code with C-level control over memory layout and allocation.
The majority of PL enthusiasts might well be interested in other aspects of computer science, but I was pointing out the the converse isn't true: the majority of people interested in the more challenging aspects of comp sci are not necessarily interested in programming languages, which is why this would be a bad filter.
I drool over Rust, too, but I wouldn't switch my company's (little) C++ code to Rust tomorrow. Also, Rust appeals mostly to C/C++ programmers, who don't usually need as many OSS/OTS libraries as application-level programmers (and those, usually specialized, libraries they do need, either work with Rust or don't; if they don't, that alone would be a deal breaker).
People who risk their company's investment (or make any important decision) based on stuff they drool over, might need to get their priorities straight.
As primarily a Scala programmer, Rust appeals greatly to me. It's basically the same language without cruft inherited from Java, and its much more amenable to optimisation that Java. For example, large heaps have unacceptable GC pauses, so projects like Cassandra invest a lot of effort into "off-heap" memory management (i.e. manual memory management). With Rust that just works a whole heap better (pun intended).
People tend to talk about "expressiveness" when discussing programming languages, which usually mean concision. I'm much more interested in what I call "expressive width", which means how high- and low-level can get in a language. PHP is little expressive width, because its runtime is so poor. Scala has good expressive width because I can play with threads, CAS operations, mem-mapped files, and even manual memory management (which is going quite far off-piste, but possible with sun.Unsafe). Rust has even more expressive width than Scala.
[Rust needs higher-kinded types before it will truly make me happy. I believe they'll arrive soonish.]
For your other points:
- P(interested in PL | interested in CS) != P(interested in CS | interested in PL).
Agreed, but I don't think it matters. Anyone interested in discrete maths (so, CS) will pick up Haskell quickly.
- "People who risk their company's investment (or make any important decision) based on stuff they drool over, might need to get their priorities straight."
Depends on your company's size and ethos. I'd rather have a few great people than a room full of monkeys, but I understand arguments that go the other way.
Many of the super programmers at google have PL research backgrounds! Like Jeff Dean. Most of the others are in systems, which are fairly aligned, and often both. Such PL enthusiasts are the last ones to try and switch the language being used.
> Such PL enthusiasts are the last ones to try and switch the language being used.
As a PL enthusiast myself, I agree with this.
By the time I had my first job out of college, I'd written programs in some twenty-odd different PLs, and felt comfortable with many of them. My employer needed me to learn SAS, so I did. They wanted some code written in Java, so I wrote it. Neither SAS nor Java is particularly fun to program in the way Haskell et al. are, but that's what they wanted, and I could do it.
There was a whole team of Java guys, and when asked to learn SAS they sat around bemoaning it and whining about how Java is so much better. "Why not just do it in Java?" they asked.
I've run into similar experiences at every company since. If people don't want Java, they want C++ or Perl. If someone writes a utility in Python, there are complainers. Some programmers will refuse to even use a particular program if it's not written in their language of choice.
In my experience, it's usually the people who aren't PL enthusiasts that are more opinionated about language choice, simply because they're less flexible.
That means it's a great filter, though, in one way—it has high precision but low recall. If you're building a smallish team on a lowish budget then precision is vital and recall isn't.
Assuming the remaining population is sufficient (which, for Haskell, for a smallish team, in a job that can be done remotely or is in a tech hot-spot, it probably is).
