Introduction
A Ruby is a dynamic, open-source programming language that focuses on productivity and simplicity. The syntax of Ruby is natural and easy to understand for users. Ruby is a popular language for many things, from web development to data analysis. Ruby programming language is highly flexible, and developers can change how the language works due to its flexibility. Ruby is an interpreted language.
Like any other programming language, Ruby also contains terms such as methods, procs lambdas, and closures. So let us see what these terms are in detail concerning the ruby.
Methods, Procs, Lambda, and closures
- A method in ruby is a named block of parameterized code connected with multiple objects. Many Languages compare functions and methods, but because ruby is a purely object-oriented language, all methods are true methods connected with at least one object. Methods are an important part of syntax in ruby, but they are not values that Ruby programs can operate on.
Example:
def factorial(m)
if m < 1 # Test the argument value for validity
raise "argument must be > 0"
elsif m == 1 # If the argument is 1
1 # then the value of the method invocation is 1
else # Otherwise, the factorial of m is m times
m * factorial(m-1) # the factorial of m-1
end
end
-
Blocks such as methods are not objects that can be manipulated by Ruby. But it's possible to create an object that constitutes a block. A proc object represents a block in Ruby. Similar to the Method object, we can implement the code of a block through the Proc that constitutes it.
- Procs are of two varieties known as procs and lambdas, which have somewhat different behavior. Procs and lambdas are both functions instead of methods invoked on an object. An essential feature of procs and lambdas is that they are closures, which means they keep access to the local variables that were in scope when they were defined, although the procs and lambda are invoked from a different scope.
Method Objects
Ruby has strong metaprogramming capabilities, and methods can be represented as instances of the Method class. Invoking a method through a Method Object is less efficient than invoking it directly. Method objects are not generally used as frequently as procs and lambdas. The Object class defines a method named "method." When we Pass it a method name as a string or a symbol, it returns a Method object representing the designated Method of the receiver.
For example:
m = 0.method(:succ) # A Method representing the succ method of Fixnum 0
Though the Method class behaves like a subclass of Proc, it is not. Method objects are initiated with the call method, similar to Proc objects. To invoke the method Method m:
puts m.call # Same as puts 0.succ. Or use puts m[].
Method objects work similar to Proc objects and can usually be used in place of them; When a true Proc is needed, we can use Method.to_proc to convert a Method into a Proc. That's why Method objects can be prefixed and passed to a method in place of a block.
For example:
def square(x); x*x; end
puts (1..10).map(&method(:square))
The main difference between Proc objects and Method objects is that Method objects are not closures. Methods in Ruby are considered completely self-contained and never have access to local variables outside of their scope. The only binding retained by a Method object is the value of self, which means the object into which the method is to be initiated.
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