YARD for documentation in Ruby - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this YARD documentation comment parsing?

Given the following Ruby method with YARD comments, what will be the description extracted by YARD for the method `greet`?

Ruby

##
# Greets a person with their name.
#
# @param name [String] the name of the person
# @return [String] greeting message
#
def greet(name)
  "Hello, #{name}!"
end

A "Hello, #{name}!"

B "greet method"

C "Greets a person with their name."

D "@param name [String] the name of the person"

💡 Hint

Look at the first comment line after the ## marker.

YARD uses the first comment line after the ## as the method description. The @param and @return tags provide additional metadata but are not the main description.

🧠 Conceptual

intermediate

Which YARD tag documents the return type of a method?

In YARD documentation, which tag is used to specify what a method returns?

A @return

B @param

C @yield

D @example

💡 Hint

It describes the output of the method.

The @return tag documents the return value and its type for a method in YARD.

🔧 Debug

advanced

Why does this YARD comment fail to document the method parameter?

Examine the following YARD comment and method. Why will YARD not recognize the parameter documentation correctly? ## # Calculates the square of a number. # @param num the number to square # @return [Integer] the squared result # def square(number) number * number end

Ruby

##
# Calculates the square of a number.
# @param num the number to square
# @return [Integer] the squared result
#
def square(number)
  number * number
end

A The comment block is missing the initial # marker.

B The @param tag is missing the type specification in brackets.

C The method is missing a return statement.

D The parameter name in @param does not match the method parameter name.

💡 Hint

Check if the parameter names match exactly.

YARD requires the parameter name in the @param tag to exactly match the method's parameter name to link documentation correctly.

📝 Syntax

advanced

Which YARD comment block is syntactically correct for documenting a method?

Choose the correctly formatted YARD comment block for this method: def add(a, b) a + b end

A

## Adds two numbers.
@param a [Integer]
@param b [Integer]
@return [Integer]

B

##
# Adds two numbers.
# @param a [Integer]
# @param b [Integer]
# @return [Integer]

C

# Adds two numbers.
# @param a Integer
# @param b Integer
# @return Integer

D

##
# Adds two numbers.
@param a [Integer]
@param b [Integer]
@return [Integer]

💡 Hint

YARD comment blocks start with ## and each line begins with #.

Option B uses the correct YARD syntax: a comment block starting with ## and each line starting with #, with tags properly formatted.

🚀 Application

expert

How many methods will YARD document in this Ruby class?

Consider this Ruby class with YARD comments. How many methods will YARD generate documentation for? class Calculator ## # Adds two numbers # @param x [Integer] # @param y [Integer] # @return [Integer] def add(x, y) x + y end # Subtracts y from x def subtract(x, y) x - y end ## # Multiplies two numbers # @param x [Integer] # @param y [Integer] # @return [Integer] def multiply(x, y) x * y end end

Ruby

class Calculator
  ##
  # Adds two numbers
  # @param x [Integer]
  # @param y [Integer]
  # @return [Integer]
  def add(x, y)
    x + y
  end

  # Subtracts y from x
  def subtract(x, y)
    x - y
  end

  ##
  # Multiplies two numbers
  # @param x [Integer]
  # @param y [Integer]
  # @return [Integer]
  def multiply(x, y)
    x * y
  end
end

A 2

B 3

C 1

D 0

💡 Hint

YARD only documents methods with comment blocks starting with ##.

YARD documents methods with comment blocks starting with ##. The 'add' and 'multiply' methods have such blocks, but 'subtract' only has a single # comment, so it is not documented.