TL;DR

1. As noted earlier, transducers can be properly annotated in Clojure using core.typed and they probably should be.
2. But... there are a few tricks necessary to make it work.
3. Transducers in Scala require tricks too, but different ones.
4. Oh, but they're so lovely in Haskell.

Update 2015-01-12

Were you led here by Clojure Gazette? Eric Normand is usually more discriminating, but don't worry, this will only waste a little of your time. Per the previous batch of updates, just below, and various subsequent posts on more or less the same topic, it should be clear this wee bagatelle …

TL;DR

• There was this perplexing article in Ars Technica about replacing Fortran for scientific computation.
• The main performance advantage of Fortran is that its restrictive data structures facilitate vector optimization.
• There are many ways to match and even outperform Fortran, while using other languages.
• But it's OK to use Fortran if you want to.
• Ars Technica notwithstanding, Clojure, Haskell and Julia are not locked in competition to replace Fortran.
• Ars Technica notwithstanding, Fibonacci sequences may be something we learned about once, but it is difficult to disguise their irrelevance to scientific computing.

Preamble

Ten or fifteen pages into a …