![]() These features are implemented in Ruby by means of code blocks, Proc objects, and methods (that are also objects)-concepts that are closely related and yet differ in subtle ways. Ruby provides the programmer with a set of very powerful features borrowed from the domain of functional programming, namely closures, higher-order functions, and first-class functions. ![]() Yield may then be used.ĭef method_call yield end method_call ( & someBlock ) Understanding blocks, Procs and methods Introduction A Proc object will be created and assigned to the parameter containing the block passed in.Īlso similar to the ampersand operator, a Proc object preceded by an ampersand during a method call will be replaced by the block that it contains. ![]() This indicates that the function expects a code block to be passed in. Much like the asterisk, the ampersand(&) may precede the last parameter of a function declaration. Specifying the names whenever they are used makes the resulting function calls very readable. Keyword Arguments are especially helpful whenever there is a lot of non-required options that might be passed into a function. ![]() Note that this does mean that you 'have' to pass on names for (in this case) the 'c' and 'd' values you pass into the function, whenever you want to include them Calling the method like test_method(1,2,3,4) will not work. In this example, parentheses are again not required unless you want to chain the result to another function or method right away. Def test_method ( a, b, c : true, d : false ) puts a, b, c, d endĪbove function can now be called as test_method(1,2), test_method(1,2, c: somevalue), test_method(1,2, d:someothervalue), test_method(1,2, c:somevalue, d:someothervalue) or even test_method(1,2, d: someothervalue, c: somevalue). ![]()
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