Programming Groovy 2

2.8 Operator Overloading

We can use Groovy’s support for operator overloading—judiciously—to create DSLs (see Chapter 19, ​Creating DSLs in Groovy​). When Java has no support for operator overloading, how does Groovy get away with that? It’s really simple: each operator has a standard mapping to methods.[16] In Java we can use those methods, and on the Groovy side we can use either the operators or their corresponding methods.

Here’s an example to show operator overloading in action:

for(ch = 'a'; ch < 'd'; ch++) {
  println ch
}

We’re looping through the characters ​a​ through ​c​ using the ​++​ operator. This operator maps to the ​next​ method on the ​String​ class to produce this output: ...