Evolution of Pattern Matching in C# Development

Pattern matching in C# has evolved rapidly, enabling simpler and more readable code, especially with switch statements.

### The Evolution of Pattern Matching in C#
* "Pattern matching" in C# allows you to **test a value's shape** and **extract information** when it matches the expected shape.
* 📜 In C# 5, developers used the "is" keyword to check if a value was of a specific type, but it only returned a **boolean result**.
* 🔢 C# 6 introduced **auto-implemented read-only properties** and **exception filters**, which were a precursor to **more advanced pattern matching features**.
* 🎯 In C# 7, pattern matching with the "is" keyword was enhanced to include an identifier, **simplifying the extraction of values**.
* 🔄 With switch statements in C# 7, patterns no longer needed to be constants, enabling **more flexible and expressive matching**.
* 🔀 Patterns in switch statements could now include **complex expressions**, such as checking **specific property values** or handling **null cases**.
* ⚡ Additionally, C# 7 introduced "throw expressions," allowing **"throw" to be used as part of an expression** rather than just a statement.

### C# Pattern Matching and Switch Expressions Deep Dive
* C# pattern matching allows for matching objects against patterns, such as property values, in switch statements to **execute corresponding code blocks**.
* ➡ "It's like destructuring, although it's not destructuring. It's saying, 'Hey, if it's a car and it meets this expression test, then **this is the value I want to return**'."
* 🔄 Discards, introduced in C# 7, are **temporary dummy variables intentionally unused**, often used in pattern matching to **ignore certain values**.
* 🎯 Switch expressions, introduced in C# 8, provide a more **concise and expressive way** to write switch statements, and they support **pattern matching**.
* 🛠 "This code might look really unfamiliar to seasoned C# developers, as it's based on a sample that's in the docs, and it's on GitHub, so you'll be able to **follow along**."
* 🔀 Switch expressions can be used in places where expressions are allowed, such as **ternary operators** and **lambda expressions**.
* 🔍 Pattern matching syntax allows for complex patterns using the `when` keyword, enabling **more advanced matching scenarios**.
* 🔮 "It's beginning to feel a little bit more like some Elixir constructs, where you say, 'Hey, if it's a struct where the **first parameter has this** and the **second one I don't care**, and the **third one has this**, then **run this code**'."

### C# 9 Pattern Matching: A Powerful Feature for Writing Cleaner Code
* C# 9 pattern matching allows developers to write cleaner code by **modularizing logic based on different patterns or conditions**.
* 📦 "Pattern matching makes it easier for you to **step by step implement a complex set of calculations**," as demonstrated in Bill Wagner's tutorial to build type-driven and data-driven algorithms.
* 🎓 Developers need to be on **.NET 5** to use **C# 9 pattern matching features**.
* 🔄 The order of case statements in the new switch statement matters, as it **stops at the first match**.
* 🔗 The official definition of pattern matching in the C# documentation provides a **comprehensive guide**.
* 🚀 Leveraging pattern matching with tuples, anonymous types, and other C# features can lead to **more concise and readable code**.
* 📈 C# 9 pattern matching is a **forward-compatible feature** that can help developers **enhance their coding skills and productivity**.
* 👥 Exploring pattern matching in other languages and learning from their implementations can **further broaden a developer's perspective and knowledge**.

Pattern Matching features in C#

The Dev Talk Show

The Dev Talk Show: Evolution of Pattern Matching in C#

The hosts discuss the rapid evolution of C# in recent years, with frequent and significant updates to the language.

They highlight the importance of paying attention to the smaller improvements and changes made by the C# team to make the developers' job easier.

The conversation touches on the fundamental impact of features like generics, LINQ, async/await, and the introduction of pattern matching in C#.

Discussing Pattern Matching in C# Programming

The discussion involves the definition of pattern matching and its potential benefits in C# programming.

They also talk about the history of pattern matching in C# and how to constrain the language version in Visual Studio.

The conversation includes a demonstration of C# 5 and C# 6 class structures, highlighting the use of auto-implemented properties and the introduction of read-only automatically implemented properties.

Discussion on C Sharp and Pattern Matching

The show discusses the use of pattern matching in C Sharp and its comparison to other languages.

It also explores the use of string formatting in C Sharp 5 versus string interpolation in C Sharp 6.

The program demonstrates the use of the "is" keyword for type checking and discusses the evolution of pattern matching constructs in C Sharp 6.

C# 6 introduced auto-implemented read-only properties and exception filters as a hint of the upcoming pattern matching feature.

The introduction of pattern matching in C# 7 allowed for more advanced and subtle matching techniques.

The development from C# 6 to 7 showcased the progression towards more powerful and flexible language features.

The is keyword in C# 7 allows for a cleaner way to cast and check types, improving code readability.

Pattern matching in switch statements in C# 7 enables the testing of non-constant patterns, providing more flexibility in code execution.

C# features like expression-bodied members have been enhanced in later versions to allow for more complex expressions and additional pattern matching capabilities, including the ability to test for specific property values.

C# 7 introduces new features such as throw expressions, pattern matching, and the discard.

Throw expressions allow for the use of throw as an expression, rather than just a statement.

Pattern matching enables a more powerful switch statement, providing a better alternative to nested if-else statements.

The discard, inspired by F# and Elixir, allows developers to ignore and handle certain cases more effectively, improving code readability.

Discussion on Code Structure and Formatting

The conversation covers the frustration with complex code structures and the use of different formatting shortcuts.

It also touches on the challenges of configuring and adapting to different shortcut keys in Visual Studio and Visual Studio Code.

The discussion then moves on to a more complex example of creating a toll calculator based on different vehicle types and their respective toll amounts.

The process involves moving values into a database, implementing the entity framework, applying the repository pattern, and using dependency injection, all while emphasizing the importance of writing unit tests.

Using Switch Expressions in C# for Calculating Vehicle Tolls

Switch expressions in C# allow for a more concise and expressive way to calculate tolls based on the type of vehicle.

The traditional switch statement can now be replaced with a more compact and readable switch expression, making the code more streamlined.

The introduction of pattern matching in C# 9 further enhances the capabilities of switch expressions, providing more flexibility in handling different cases.

The Evolution of Pattern Matching Features in C#

Pattern matching features in C# have been introduced in different versions, including 7, 7.

2, 8, and 9, leading to some frustration due to the layered implementation.

The use of discards in C# 8 is essential for certain tests and the compiler provides helpful suggestions for their use.

Switch expressions and traditional switch statements in C# can be utilized with different method syntax, including lambda and traditional method declaration.

Using Switch Expressions for Pattern Matching in C#

Switch expressions can be used in expressions like the ternary operator and lambdas, allowing for more flexibility than switch statements.

The syntax for switch expressions allows for pattern matching, providing the ability to match the shape and properties of an object.

This functionality is similar to pattern matching in languages like Elixir, offering a visual way to match the shape of an object and providing more flexibility in code.

Complex pattern matching in C# allows for flexible syntax, including the use of when and switch statements.

The tutorial by Bill Wagner demonstrates how pattern matching can simplify the implementation of complex calculations step by step.

The use of tuples in the switch expression enables the handling of more complex scenarios, providing a more powerful syntax in C# code.

The new tuple syntax in C# allows for cleaner and more concise code when handling multiple values for a calculation.

Pattern matching with the switch statement provides a simpler and more readable way to handle different cases based on conditions.

The introduction of non-constant cases in the switch statement has been a significant change in the language, allowing for more flexibility in code organization.

Mind-Bending Changes in C# 9 Pattern Matching

The order of switch evaluations in C# 9 can now impact the matching result, which was not possible before, requiring developers to be mindful of the switch statement's order.

Unit testing and careful consideration of the switch order are now crucial to avoid overlapping and incorrect matches.

The use of C# 9 pattern matching features requires .

NET 5, which is essential to keep in mind when starting a new project.

Using tools like Resharper can help convert code into a switch expression for easier memorization.

Understanding C# language versioning and pattern matching is crucial for writing efficient code.

NET platform can be easily accessed through dotnet.

com for downloading and using the latest versions.

The Usefulness of QR Codes in Sharing Resources

Using QR codes for sharing resources can be helpful in presentations and videos, as it provides an easy way for viewers to access links without having to write them down.

QR codes make it convenient for people to access resources from videos, where they can't click on links.

Shortening QR code links with tools like Bitly allows for tracking the number of people who access the resources.

Upcoming Changes to the Dev Talk Show Schedule

The Dev Talk Show is moving to an earlier time of 7:30 PM US Eastern Time due to the upcoming change to UTC-5.

Viewers are encouraged to provide feedback on pattern matching and share information about it in other languages.

The show also announced upcoming events and encouraged audience members to join the conversation on Twitter.