What Is A Proc ?

Certainly! Here's a detailed answer to the interview question "What is a Proc in Ruby on Rails?":

What Is A Proc?

In Ruby, a Proc (short for "procedure") is an object that encapsulates a block of code, which can be stored in a variable, passed to methods, and executed. Procs are a fundamental part of Ruby's support for functional programming and are used extensively in Ruby on Rails for various purposes, such as callbacks, filters, and more.

Key Characteristics of a Proc

1. Encapsulation of Code: A Proc object holds a block of code that can be executed at a later time. This allows for greater flexibility and reusability of code.

2. Creation: You can create a Proc object using the Proc.new method or the proc keyword. For example:

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   my_proc = Proc.new { |x| x * 2 }
   # or
   my_proc = proc { |x| x * 2 }

3. Execution: A Proc can be executed using the call method:

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   result = my_proc.call(5)  # result is 10

4. Closures: Procs are closures, meaning they capture the surrounding context in which they were defined. This allows them to access variables that were in scope at the time of their creation:

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   multiplier = 3
   my_proc = Proc.new { |x| x * multiplier }
   result = my_proc.call(5)  # result is 15

5. Argument Handling: Procs are lenient with the number of arguments passed to them. They do not raise an error if the number of arguments does not match the number of parameters:

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   my_proc = Proc.new { |x, y| x + (y || 0) }
   result = my_proc.call(5)  # result is 5

Use Cases in Ruby on Rails

1. Callbacks: Procs are often used in Rails for defining callbacks, such ...