Principes de développement

La programmation est un parcours d'amélioration continue. Au fur et à mesure que nous acquérons de l'expérience, nous rencontrons des pratiques et des principes qui nous aident à affiner notre métier, conduisant à un code de meilleure qualité. Cet article vous guidera à travers les principes et pratiques clés qui peuvent vous aider à devenir un meilleur programmeur, notamment les principes SOLID, les modèles de conception et les normes de codage. Nous explorerons comment ces concepts peuvent améliorer votre processus de développement.

Remarque sur les exemples : j'ai choisi Go pour les exemples de code en raison de sa simplicité et de sa lisibilité – il est souvent décrit comme un « pseudocode exécutable ». Si vous n'êtes pas familier avec Go, ne vous inquiétez pas ! C'est une excellente occasion d'apprendre.

Lorsque vous rencontrez une syntaxe ou des concepts inconnus, prenez un moment pour les rechercher. Ce processus de découverte peut être un bonus amusant à votre expérience d'apprentissage. N'oubliez pas que les principes dont nous discutons s'appliquent à tous les langages de programmation, alors concentrez-vous sur la compréhension des concepts plutôt que sur les spécificités de la syntaxe Go.

1. Adoptez les normes de programmation

L'une des premières étapes pour devenir un meilleur programmeur est d'adhérer aux normes de programmation. Les normes fournissent des lignes directrices sur des aspects tels que les conventions de dénomination, l'organisation du code et la structure des fichiers. En suivant ces conventions, vous vous assurez que votre code est cohérent et facile à lire, ce qui est crucial pour la collaboration et la maintenance à long terme.

Chaque langage de programmation a généralement son propre ensemble de conventions. Pour Go, ceux-ci sont décrits dans le guide de style officiel de Go. Il est important d'apprendre et d'adopter les normes pertinentes à votre contexte, qu'il s'agisse des conventions de votre équipe ou des directives spécifiques à la langue.

Regardons un exemple de la façon dont les normes suivantes peuvent améliorer la lisibilité du code :

// Before: Inconsistent styling
func dosomething(x int,y string)string{
if x>10{
return y+"is big"
}else{
return y+"is small"
}}

Ce code présente plusieurs problèmes :

1. Un espacement et une indentation incohérents rendent difficile la compréhension de la structure du code.
2. Le nom de la fonction ne suit pas la convention camelCase de Go.
3. La clause else inutile ajoute une complexité cognitive.

Maintenant, refactorisons ce code pour suivre les standards Go :

// After: Following Go standards
func doSomething(x int, y string) string {
    if x > 10 {
        return y + " is big"
    }
    return y + " is small"
}

Dans cette version améliorée :

1. Une indentation appropriée montre clairement la structure du code.
2. Le nom de la fonction suit la convention de dénomination de Go.
3. La clause else est supprimée, simplifiant la logique.

Ces changements ne concernent pas seulement l’esthétique ; ils améliorent considérablement la lisibilité et la maintenabilité du code. Lorsque vous travaillez en équipe, l'application cohérente de ces normes permet à chacun de comprendre et de travailler plus facilement avec la base de code.

Même si votre équipe n'a pas de normes établies, vous pouvez prendre l'initiative de suivre les conventions largement acceptées dans la communauté des développeurs. Au fil du temps, cette pratique conduira à un code plus lisible et maintenable dans vos projets.

2. Suivez les principes de conception

Les principes de conception de programmation sont des lignes directrices qui vous aident à écrire un meilleur code. Ces principes peuvent être appliqués non seulement à l'architecture du code mais également à la conception de systèmes et même à certains aspects des processus de développement.
Il existe de nombreux principes de conception, et certains sont plus pertinents dans des contextes spécifiques. D'autres sont plus généraux comme KISS (Keep It Simple, Stupid) ou YAGNI (You Ain't Gonna Need It).
Parmi ces principes généraux, les principes SOLID sont parmi les plus percutants. Explorons chaque principe en mettant l'accent sur la façon dont ils peuvent améliorer votre code.

Principe de responsabilité unique (SRP)

Ce principe vous encourage à concevoir des composants (fonctions, classes ou modules) avec un objectif unique et bien défini. Lorsqu'un composant a plusieurs responsabilités, il devient plus difficile à comprendre, à tester et à maintenir.

Regardons un exemple de refactorisation d'une fonction pour adhérer au SRP :

// Before: A function doing too much
func processOrder(order Order) error {
    // Validate order
    if order.Total <= 0 {
        return errors.New("invalid order total")
    }
    // Save to database
    db.Save(order)
    // Send confirmation email
    sendEmail(order.CustomerEmail, "Order Confirmation", orderDetails(order))
    // Update inventory
    for _, item := range order.Items {
        updateInventory(item.ID, item.Quantity)
    }
    return nil
}

Cette fonction effectue plusieurs tâches indépendantes : valider la commande, l'enregistrer dans la base de données, envoyer un e-mail et mettre à jour l'inventaire. Décomposons-le en fonctions distinctes, chacune avec une seule responsabilité :

// After: Breaking it down into single responsibilities
func processOrder(order Order) error {
    if err := validateOrder(order); err != nil {
        return err
    }
    if err := saveOrder(order); err != nil {
        return err
    }
    if err := sendOrderConfirmation(order); err != nil {
        return err
    }
    return updateInventoryForOrder(order)
}

Maintenant, implémentons chacune de ces fonctions :

func validateOrder(order Order) error {
    if order.Total <= 0 {
        return errors.New("invalid order total")
    }
    return nil
}

func saveOrder(order Order) error {
    return db.Save(order)
}

func sendOrderConfirmation(order Order) error {
    return sendEmail(order.CustomerEmail, "Order Confirmation", orderDetails(order))
}

func updateInventoryForOrder(order Order) error {
    for _, item := range order.Items {
        if err := updateInventory(item.ID, item.Quantity); err != nil {
            return err
        }
    }
    return nil
}

Dans cette version refactorisée :

• Chaque fonction a une responsabilité unique et claire.
• Le code est plus modulaire et plus facile à tester.
• Les composants individuels peuvent être réutilisés ou modifiés sans affecter les autres.

Faites-moi confiance, votre futur vous vous remerciera pour ce niveau d'organisation.

Principe Ouvert-Fermé (OCP)

Le principe ouvert-fermé conseille que les entités logicielles doivent être ouvertes pour extension mais fermées pour modification. Cela signifie que vous devriez pouvoir ajouter de nouvelles fonctionnalités sans modifier le code existant.

Liskov Substitution Principle (LSP)

LSP states that objects of a superclass should be replaceable with objects of its subclasses without affecting the correctness of the program. This ensures that inheritance hierarchies are well-designed and maintainable.

Interface Segregation Principle (ISP)

ISP suggests that no code should be forced to depend on methods it does not use. In practice, this often means creating smaller, more focused interfaces.This modularity makes your code easier to manage and test.

Here's an example demonstrating ISP:

// Before: A large interface that many structs only partially implement
type Worker interface {
    DoWork()
    TakeBreak()
    GetPaid()
    FileTicket()
}

This large interface forces implementers to define methods they might not need. Let's break it down into smaller, more focused interfaces:

// After: Smaller, more focused interfaces
type Worker interface {
    DoWork()
}

type BreakTaker interface {
    TakeBreak()
}

type Payable interface {
    GetPaid()
}

type TicketFiler interface {
    FileTicket()
}

Now, structs can implement only the interfaces they need:

type Developer struct{}

func (d Developer) DoWork() {
    fmt.Println("Writing code")
}

func (d Developer) TakeBreak() {
    fmt.Println("Browsing Reddit")
}

func (d Developer) FileTicket() {
    fmt.Println("Creating a Jira ticket")
}

type Contractor struct{}

func (c Contractor) DoWork() {
    fmt.Println("Completing assigned task")
}

func (c Contractor) GetPaid() {
    fmt.Println("Invoicing for work done")
}

This modularity makes your code easier to manage and test. In Go, interfaces are implicitly implemented, which makes this principle particularly easy to apply.

Dependency Inversion Principle (DIP)

DIP promotes the use of abstractions rather than concrete implementations. By depending on interfaces or abstract classes, you decouple your code, making it more flexible and easier to maintain. This also facilitates easier testing by allowing mock implementations.

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Applying the SOLID (see what I did there?) principles leads to decoupled, modular code that is easier to maintain, scale, reuse, and test. I’ve found that these principles, while sometimes challenging to apply at first, have consistently led to more robust and flexible codebases.

While these principles are valuable, remember that they are guidelines, not strict rules.There will always be exceptions to the rules, but it’s important to remember that following these principles is a continuous process and not a one-time event. It will take time and effort to develop good habits, but the rewards are well worth it.

3. Utilize Design Patterns

Design patterns provide reusable solutions to common programming problems. They are not rigid implementations but rather templates that can be adapted to fit specific needs. Many design patterns are related to SOLID principles, often aiming to uphold one or more of these principles in their design.

Design patterns are typically categorized into three types:

Creational Patterns

These patterns deal with object creation mechanisms. An example is the Factory Method pattern, which creates objects based on a set of criteria while abstracting the instantiation logic.

Let's look at a simple Factory Method example in Go:

type PaymentMethod interface {
    Pay(amount float64) string
}

type CashPayment struct{}

func (c CashPayment) Pay(amount float64) string {
    return fmt.Sprintf("Paid %.2f using cash", amount)
}

type CreditCardPayment struct{}

func (cc CreditCardPayment) Pay(amount float64) string {
    return fmt.Sprintf("Paid %.2f using credit card", amount)
}

Here, we define a PaymentMethod interface and two concrete implementations. Now, let's create a factory function:

func GetPaymentMethod(method string) (PaymentMethod, error) {
    switch method {
    case "cash":
        return CashPayment{}, nil
    case "credit":
        return CreditCardPayment{}, nil
    default:
        return nil, fmt.Errorf("Payment method %s not supported", method)
    }
}

This factory function creates the appropriate payment method based on the input string. Here's how you might use it:

method, err := GetPaymentMethod("cash")
if err != nil {
    fmt.Println(err)
    return
}
fmt.Println(method.Pay(42.42))

This pattern allows for easy extension of payment methods without modifying existing code.

Structural Patterns

Structural patterns deal with object composition, promoting better interaction between classes. The Adapter pattern, for example, allows incompatible interfaces to work together.

Behavioral Patterns

Behavioral patterns focus on communication between objects. The Observer pattern is a common behavioral pattern that facilitates a publish-subscribe model, enabling objects to react to events.

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It's important to note that there are many more design patterns, and some are more relevant in specific contexts. For example, game development might heavily use the Object Pool pattern, while it's less common in web development.

Design patterns help solve recurring problems and create a universal vocabulary among developers. However, don't feel pressured to learn all patterns at once. Instead, familiarize yourself with the concepts, and when facing a new problem, consider reviewing relevant patterns that might offer a solution. Over time, you'll naturally incorporate these patterns into your design process.

4. Practice Good Naming Conventions

Clear naming conventions are crucial for writing readable and maintainable code. This practice is closely related to programming standards and deserves special attention.

Use Descriptive Names

Choose names that clearly describe the purpose of the variable, function, or class. Avoid unnecessary encodings or cryptic abbreviations.

Consider this poorly named function:

// Bad
func calc(a, b int) int {
    return a + b
}

Now, let's improve it with more descriptive names:

// Good
func calculateSum(firstNumber, secondNumber int) int {
    return firstNumber + secondNumber
}

However, be cautious not to go to the extreme with overly long names:

// Too verbose
func calculateSumOfTwoIntegersAndReturnTheResult(firstInteger, secondInteger int) int {
    return firstInteger + secondInteger
}

Balance Clarity and Conciseness

Aim for names that are clear but not overly verbose. Good naming practices make your code self-documenting, reducing the need for excessive comments.

Prefer Good Names to Comments

Often, the need for comments arises from poorly named elements in your code. If you find yourself writing a comment to explain what a piece of code does, consider whether you could rename variables or functions to make the code self-explanatory.

Replace Magic Values with Named Constants

Using named constants instead of hard-coded values clarifies their meaning and helps keep your code consistent.

// Bad
if user.Age >= 18 {
    // Allow access
}

// Good
const LegalAge = 18
if user.Age >= LegalAge {
    // Allow access
}

By following these naming conventions, you'll create code that's easier to read, understand, and maintain.

5. Prioritize Testing

Testing is an essential practice for ensuring that your code behaves as expected. While there are many established opinions on testing methodologies, it's okay to develop an approach that works best for you and your team.

Unit Testing

Unit tests focus on individual modules in isolation. They provide quick feedback on whether specific parts of your code are functioning correctly.

Here's a simple example of a unit test in Go:

func TestCalculateSum(t *testing.T) {
    result := calculateSum(3, 4)
    expected := 7
    if result != expected {
        t.Errorf("calculateSum(3, 4) = %d; want %d", result, expected)
    }
}

Integration Testing

Integration tests examine how different modules work together. They help identify issues that might arise from interactions between various parts of the code.

End-to-End Testing

End-to-end tests simulate user interactions with the entire application. They validate that the system works as a whole, providing a user-centric view of functionality.

Remember, well-tested code is not only more reliable but also easier to refactor and maintain over time. The SOLID principles we discussed earlier can make testing easier by encouraging modular, decoupled code that is simpler to isolate and validate.

6. Take Your Time to Plan and Execute

While it might be tempting to rush through projects, especially when deadlines are tight, thoughtful planning is crucial for long-term success. Rushing can lead to technical debt and future maintenance challenges.

Take the time to carefully consider architectural decisions and plan your approach. Building a solid foundation early on will save time and effort in the long run. However, be cautious not to over-plan—find a balance that works for your project's needs.

Different projects may require varying levels of planning. A small prototype might need minimal upfront design, while a large, complex system could benefit from more extensive planning. The key is to be flexible and adjust your approach based on the project's requirements and constraints.

Conclusion

By following these principles and practices, you can become a better programmer. Focus on writing code that is clear, maintainable, and thoughtfully structured. Remember the words of Martin Fowler: "Any fool can write code that a computer can understand. Good programmers write code that humans can understand."

Becoming a better programmer is a continuous process. Don't be discouraged if you don't get everything right immediately. Keep learning, keep practicing, and most importantly, keep coding. With time and dedication, you'll see significant improvements in your skills and the quality of your work.

Here are some resources you might find helpful for further learning:

• For general programming principles: Programming Principles
• For understanding the importance of basics: The Basics
• For a deep dive into software design: The Philosophy of Software Design and its discussion
• For practical programming advice: The Pragmatic Programmer
• For improving existing code: Refactoring

Now, armed with these principles, start applying them to your projects. Consider creating a small web API that goes beyond simple CRUD operations, or develop a tool that solves a problem you face in your daily work. Remember, the best way to learn is by doing. Happy coding!

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