Look before you leap

Look before you leap is a principle that emphasizes the importance of verifying the state of a program before executing an action. This principle is particularly useful when working with data structures, as it allows you to check if the data is valid and avoid potential errors or bugs.

In Ruby, there are several ways to implement the Look before you leap principle. Here are some examples:

Checking for Nil Values

In Ruby, nil is a special value that represents the absence of a value. It’s important to check for nil values before using them to avoid runtime errors.

# Example of checking for a nil value in Ruby
if my_variable.nil?
  puts "my_variable is nil"
else
  puts "my_variable is not nil"
end

Checking for an Empty Array

When working with arrays, it’s important to verify that the array is not empty before performing any actions on it.

# Example of checking for an empty array in Ruby
my_array = []
if my_array.empty?
  puts "my_array is empty"
else
  puts "my_array is not empty"
end

Checking for a Key in a Hash

When working with hashes, it’s important to verify that a key exists before accessing its value.

# Example of checking for a key in a hash in Ruby
my_hash = {a: 1, b: 2, c: 3}
if my_hash.has_key?(:d)
  puts "Key :d exists in my_hash"
else
  puts "Key :d does not exist in my_hash"
end

While the “Look before you leap” principle is useful for preventing runtime errors, it may not be sufficient in cases where exceptions can occur. This is where the begin-rescue construct comes into play.

The begin-rescue construct is used in Ruby to handle exceptions that may occur during program execution. Here’s an example:

begin
  # Code that may raise an exception
  result = 10 / 0
rescue => exception
  # Handle the exception
  puts "Error: #{exception.message}"
end

In this example, we attempt to divide the number 10 by 0, which would normally raise a ZeroDivisionError exception. However, we catch this exception using a rescue block and print an error message instead of allowing the exception to terminate the program.

The begin-rescue construct is particularly useful when dealing with situations where exceptions can occur, such as when working with external APIs or user input. However, it’s important to remember that the “Look before you leap” principle should still be applied to prevent exceptions from occurring in the first place.

The “Look before you leap” principle is a valuable programming principle that can help prevent errors and bugs in your code. While the begin-rescue construct is useful for handling exceptions, it’s important to verify the state of your program before executing code to prevent exceptions from occurring in the first place. By combining the two techniques, you can write more robust and reliable code that is less prone to errors and bugs.

Crafted by Wilbur Suero, a Software Engineer, who is passionate about building innovative and impactful solutions that drive business growth and operational excellence.