The Well-Grounded Rubyist, Second Edition

14.1. Basic anonymous functions: The Proc class

At its most straightforward, the notion of a callable object is embodied in Ruby through objects to which you can send the message call, with the expectation that some code associated with the objects will be executed. The main callable objects in Ruby are Proc objects, lambdas, and method objects. Proc objects are self-contained code sequences that you can create, store, pass around as method arguments, and, when you wish, execute with the call method. Lambdas are similar to Proc objects. Truth be told, a lambda is a Proc object, but one with slightly special internal engineering. The differences will emerge as we examine each in turn. Method objects represent methods extracted into objects that ...