Programming Case Styles : Using the Conventions

Programming case styles are conventions that dictate how identifiers like variables, functions, classes, and other entities are named and formatted. Different case styles are used to improve readability and to adhere to the guidelines of various programming languages, frameworks, or projects. Here’s a detailed look at some common programming case styles:

1. Camel Case

• Description: In camel case, words are joined together without spaces, and each word starts with a capital letter, except for the first word in lower camel case.
• Variants:
  • Lower Camel Case (camelCase): The first letter of the first word is lowercase, but the first letter of each subsequent word is uppercase. Commonly used for variable and function names.
    • Example: myVariableName
  • Upper Camel Case (PascalCase): The first letter of each word is capitalized. Often used for class names and sometimes for method names, especially in languages like C# and Java.
    • Example: MyClassName

function calculateArea($base, $height) {
    return 0.5 * $base * $height;
}

$myVariableName = "A string";
$area = calculateArea(5, 10);

Upper Camel Case (PascalCase)

Used for class names.

class MyClassName {
    public $value;
    
    public function __construct($value) {
        $this->value = $value;
    }
}

$myObject = new MyClassName(10);

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2. Snake Case

• Description: In snake case, words are separated by underscores, and typically, all letters are lowercase.
• Common Usage: Widely used in languages like Python and Ruby for variable names, function names, and file names.
• Example: my_variable_name

function calculate_area($base, $height) {
    return 0.5 * $base * $height;
}

$my_variable_name = "A string";
$area = calculate_area(5, 10);

3. Kebab Case

• Description: Kebab case involves separating words with hyphens, and all letters are typically lowercase.
• Common Usage: Not commonly used in programming languages as identifiers because hyphens can be interpreted as the minus operator. However, it’s prevalent in URLs, CSS class names, and file names.
• Example: my-variable-name

// Pseudo-code, not valid PHP syntax
// $my-variable-name = "A string";  // This would cause a syntax error in PHP

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4. Screaming Snake Case

• Description: A variant of snake case where all letters are uppercase. Words are separated by underscores.
• Common Usage: Often used for constants in many programming languages to distinguish them from other variables.
• Example: MY_CONSTANT_NAME

define("MAX_SIZE", 100);
const PI = 3.14159;
$MY_CONSTANT_NAME = "A constant string";

5. Title Case

• Description: In title case, every word starts with a capital letter, and spaces are typically used to separate words. While not common in actual code due to the space character, it’s often used in the names of files, projects, or titles in documentation.
• Example: My Title Case

// Pseudo-code, used for illustrative purposes
// class My Title Case { ... }

6. Flat Case

• Description: All letters are lowercase with no separators between words. Not as common due to reduced readability, especially with longer names.
• Common Usage: Sometimes used for domain names or system identifiers where spaces and special characters are restricted.
• Example: myflatcase

$username = "user123";
$apikey = "abc123xyz";

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Notes on Usage

• The choice of case style can depend on the programming language, company coding standards, or personal preference.
• Consistency is key. Once a case style is chosen for a particular type of identifier (e.g., variable, class), it’s best practice to stick with it throughout the project.
• Some programming environments are case-sensitive (e.g., variables myvariable and MyVariable would be different), while others are not. This is another factor that influences the choice and consistency of case style usage.

When working on a team or contributing to open-source projects, adhering to the established case style guidelines is important for maintaining code readability and consistency.

Preferred Naming and Case Styles Based on the Programming Language

Preferred naming conventions can vary based on the programming language, community practices, and sometimes even the specific frameworks or libraries being used within that language. Below are the preferred case styles for some common programming languages:

1. Python

• Variables and Functions: Snake Case (snake_case)
  • Example: my_variable, calculate_area
• Classes: Pascal Case (PascalCase)
  • Example: MyClass
• Constants: Screaming Snake Case (SCREAMING_SNAKE_CASE)
  • Example: MAX_SIZE, DEFAULT_TIMEOUT

Python’s style guide, PEP 8, provides comprehensive guidelines on naming conventions and other style-related matters.

2. Java

• Variables and Functions (Methods): Camel Case (camelCase)
  • Example: myVariable, calculateArea
• Classes and Interfaces: Pascal Case (PascalCase)
  • Example: MyClass, MyInterface
• Constants: Screaming Snake Case (SCREAMING_SNAKE_CASE)
  • Example: MAX_SIZE, DEFAULT_TIMEOUT

Java follows a very consistent naming convention across the majority of its projects, and these conventions are widely accepted in the community.

3. JavaScript/TypeScript

• Variables and Functions: Camel Case (camelCase)
  • Example: myVariable, calculateArea
• Classes: Pascal Case (PascalCase)
  • Example: MyClass
• Constants: Often Screaming Snake Case (SCREAMING_SNAKE_CASE), but sometimes also Camel Case or Pascal Case, depending on the scope and constancy.
  • Example: MAX_SIZE, defaultTimeout

JavaScript and TypeScript are flexible but often follow conventions similar to Java, especially in larger codebases or frameworks.

4. C#

• Variables and Methods: Camel Case (camelCase)
  • Example: myVariable, calculateArea
• Classes, Interfaces, and Namespaces: Pascal Case (PascalCase)
  • Example: MyClass, IMyInterface, MyNamespace
• Constants and Read-only Variables: Pascal Case (PascalCase) or Screaming Snake Case (SCREAMING_SNAKE_CASE), depending on the context and developer’s preference.
  • Example: MaxSize, DEFAULT_TIMEOUT

C# conventions are largely influenced by Microsoft’s guidelines and are consistently followed in .NET projects.

5. Ruby

• Variables and Methods: Snake Case (snake_case)
  • Example: my_variable, calculate_area
• Classes and Modules: Pascal Case (PascalCase)
  • Example: MyClass, MyModule
• Constants: Screaming Snake Case (SCREAMING_SNAKE_CASE)
  • Example: MAX_SIZE, DEFAULT_TIMEOUT

Ruby follows its own set of conventions, and consistency is highly valued in the Ruby community.

6. PHP

• Variables: Snake Case (snake_case) traditionally, but Camel Case (camelCase) is also common.
  • Example: my_variable, myVariable
• Functions and Methods: Snake Case (snake_case) traditionally, but Camel Case (camelCase) is also common.
  • Example: calculate_area, calculateArea
• Classes and Interfaces: Pascal Case (PascalCase)
  • Example: MyClass, IMyInterface
• Constants: Screaming Snake Case (SCREAMING_SNAKE_CASE)
  • Example: MAX_SIZE, DEFAULT_TIMEOUT

PHP is quite flexible, and different frameworks and projects might follow different conventions. PSR (PHP Standard Recommendations) provides a set of coding standards that many modern PHP projects adhere to.

These are the general conventions, but it’s always best to consult the specific style guide or community standards for the language you’re working with, as practices can evolve over time. Additionally, when working on an existing codebase, aligning with its established conventions is typically more important than strictly following the broader language standards.

Frequently Asked Questions About Programming Case Styles