Avoiding Boilerplate Code with Metaprogramming in Ruby

Avoiding Boilerplate Code

Although metaprogramming has a straightforward notion, there are many things we may accomplish with it. Below is a list of a few metaprogramming goals:

• Code generation
• Code completion
• Code reflection
   

Now, You write a lot of repetitive code that even a trained monkey could write. You're annoyed that you have to complete this task on your own and frustrated that the repetitious code will overcrowd your class listings.

Ruby enjoys serving as the trained monkey who creates your repeated code every time. Using Module #define a method, you can define methods algorithmically.

Usually, the repetitive code is a bunch of similar methods. Suppose you need to write code like this:

class Catcher
def catcher(valof_many)
puts "Fetching #{valof_many ? valof_many : "all"}."
end
def fetching_one
catcher(1)
end


def fetch_ten
catcher(10)
end


def fetch_all
catcher(nil)
end
end

Without having to write it all out, you can specify this exact same code. Make a data structure containing the variations between the methods, and iterate over it, defining a method with define method each time:

class GeneratedCatcher
def catcher(valof_many)
puts "Fetching #{valof_many ? valof_many : "all"}."
end
[["one", 1], ["ten", 10], ["all", nil]].each do |name, number|
define_method(:"catch_#{name}") do
catch(number)
end
end
end
GeneratedFetcher.instance_methods - Object.instance_methods
# => [:fetch_one, :fetch, :fetch_ten, :fetch_all]
GeneratedFetcher.new.catch_one
# Fetching 1.
GeneratedFetcher.new.catch_all
# Fetching all.

This takes up less room in your class listing, is easier to type, and is less monkey-like coding. Instead of writing out an additional boilerplate, you can add to the data structure if you need to create more of these functions.

Writing original code has always been favoured by programmers over producing copies of existing code. We've always utilized tools to produce code since it would be time-consuming to type out manually, from lex and yacc to more recent applications like Hibernate and Cog.

Ruby programmers create code directly from Ruby rather than using an external tool.

There are two methods that have official approval. Using a defined method to construct a method whose implementation can make use of the local variables accessible at the moment it was declared is a more excellent approach. You cannot tell the difference between methods you wrote down by hand and methods whose code you wrote. If you are metaprogramming using string evaluations, as shown in the following example, they will appear in method lists and in generated RDoc documentation even produce the RDoc documentation and include it at the start of the created method

Metaprogramming is used in the built-in decorator methods that we have already examined. A method whose name and implementation are based on a string is defined by the attr_reader method, which accepts a string as an input. All of the code for the reader methods is factored out into attr_reader; you just need to provide the minimal portion that varies each time.

Frequently Asked Questions

What are Ruby lambdas?

A lambda is an object in Ruby that is comparable to a proc. A lambda returns to its calling procedure rather than exiting immediately, and unlike a proc, it needs a particular amount of arguments supplied to it.

What is a singleton class in Ruby?

A creational design pattern called singleton makes sure that there is only one object of its sort and gives all other code a single point of access to it.

Define yield in Ruby?

The Ruby keyword yield enables developers to provide arguments to blocks from the yield; there are no restrictions on the number of arguments that can be passed to a block.

What is meta class in Ruby?

Ruby automatically constructs a class to house just that function when you declare a singleton method on an object.

Why do we use blocks in Ruby?

Blocks, which resemble closures, have been a feature of the Ruby language since its beginning. When used correctly, they can minimize repetition and even make coding less prone to errors.

Conclusion

In this article, we have extensively discussed the Avoiding Boilerplate Code with Metaprogramming in Ruby.

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