[p0llard]

Probably depends on the definition of leading; I'd guess that Haskell is probably used more than any other (Turing-complete, to exclude Gallina, etc.) functional language within programming language research, but you're right that in terms of usage in industry etc. Scala is probably on top.

[pc86]

Programming language research is a pretty small and arbitrary space with regard to overall usage, isn't it?

[p0llard]

Yes it is, but if "leading functional language" means "on the cutting edge of research into functional languages" then that might well be used to describe Haskell.

If leading refers to overall usage in industry, then sure, it's not really relevant.

[fnord123]

> I'd guess

Why would you guess?

> functional language within programming language research

Why is this [more] important? Why not e.g. Erlang which almost certainly pumps more bits per day than Haskell.

[p0llard]

> Why would you guess?

Because I'm basing it on my experience doing research in PLT, but this is of course purely anecdotal and my areas of research interest lie away from the likes of Haskell, so I would not wish to make a false claim by stating it as fact.

> Why is this [more] important?

I never said that it was, only that depending on what is meant by "leading", industry usage might not be relevant. Since Scala is by far the more used language I think it's fair to assume that (without meaning to put words into mouths) the original commenter might have been talking about PLT research as opposed to usage in industry.