Question

I’ve found a groovy code snippet similar to the next one:

def f1 = { print "Hello, ${it}" }

def f2 = { "world" }​​​​​​​​

(f2 >> f1)()

It looks like such construction works only between closures. This code also works with left shift operator ((f1 << f2)()).

I wonder how is this operator (or this technique) called?

Answer 1

It does closure composition.

See the rightShift and leftShift operator overloading API docs.

Overriding shift operators is a pretty common technique, like for adding items to a collection.