Functional constructs shared by Groovy, Scala, and Clojure and their benefits

http://www.ibm.com/developerworks/java/library/j-jn10/index.html

by moondowner • 13 years ago

2 1 13 years ago

vorg• 13 years ago

So Scala...

    employees
      .filter(_.length() > 1)
      .map(_.capitalize)
      .reduce(_ + "," + _)

...Groovy...

    listOfNames
      .findAll {it.length() > 1}
      .collect {it.capitalize()}
      .join(',')

...and Clojure...

    (->> list-of-emps
      (filter #(< 1 (count %)))
      (map clojure.string/capitalize)
      (interpose ",")
      (reduce str))

They all look similar, but Clojure's syntax is harder to read for the uninitiated at first sight, one of the downsides of enabling syntactic macros and the homoiconocity it requires.

I do think there's room for a Scala/Groovy-looking syntax to sit atop Clojure, though, not to replace Clojure but to complement it. As it stands, the comparison code is easily misread and should be infix. I'm working on a tool to read this...

    listOfEmps
      ->> filter(count(_) > 1)
      ->> map(clojure.string.capitalize)
      ->> interpose(",")
      ->> reduce(str)

...and convert it to the Clojure sample above. There's been no real technical blockers (besides parsing performance of course). The bottleneck has been designing the syntax to cover all possible holes.

Functional constructs shared by Groovy, Scala, and Clojure and their benefits

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