411 REFERENCE · Wikibooks
Ruby Programming/Method Calling
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
super
The super keyword can be used to call a method of the same name in the superclass of the class making the call. Values passed to the super call are passed into the parent method.
Example:
class SomeClass
def initialize(name)
end
end
class ChildClass < SomeClass
def initialize(name, value)
super(name)
end
end
A call to the initialize function of the child class above will result in the execution of both its body and the body of the initialize function in the parent class.
Note that if you invoke super without arguments, all arguments to executing method will be passed to the parent method as well - and if parent's signature does not match the number of arguments, an exception will be raised. So, if the child version of the method uses a different number of arguments than the version in superclass, you need to list arguments that you want to pass to the parent's version of the method.
Note also that you can use any method name, not just initialize (in this case).
iterators
Iterators provide a method for cycling through a set of values and performing an operation, usually specified by a code block, for each value. Iterator functionality is often provided through the mixin Enumeration module.
The first iterator that Ruby programmers are likely to encounter is the each iterator.
Example:
arr = [1,2,3]
arr.each do |number|
put number
end
Outputs:
1
2
3
yield
yield executes the entire code block passed to the method.
Example:
def do3times
yield
yield
yield
end
do3times { puts "yielding..." }
Outputs:
yielding...
yielding...
yielding...
You can therefore make your own method looking like the built-in times:
class Fixnum
def times_plus1
i = 1
while i <= self + 1
i += 1
yield
end
end
end
5.times_plus1 { puts "yielding..." }
Outputs:
yielding...
yielding...
yielding...
yielding...
yielding...
yielding...
Ruby Control Structures Classes