Groovy Goodness: Chain Closures Together with Closure Composition

There are a lot of new features in Groovy 1.8. One of them is the possibility to compose a new closure by chaining two other closures together. We use the leftShift and rightShift operators (<< and >>) to combine multiple closures to create a new closure.

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

def convert = { new Expando(language: it) } def upper = { it.toUpperCase() }   // Composition. def upperConvert = convert << upper   def languages = ['Groovy', 'Scala', 'Clojure'].collect(upperConvert) println languages // Output: [{language=GROOVY}, {language=SCALA}, {language=CLOJURE}] assert languages[0].language == 'GROOVY' assert languages[1].language == 'SCALA' assert languages[2].language == 'CLOJURE'   // Reverse composition. def lastLetter = { it[-1] } def firstLetters = ['Groovy', 'Clojure', 'Scala'].collect(upper >> lastLetter) assert firstLetters.join() == 'YEA'

Try with Groovy web console.