Allow Matching on Primitives

Oct 13, 2025 by wbrum.org 54 views

Introduction

Pattern matching is a powerful feature in programming languages that allows developers to write more concise and expressive code. However, the current implementation of pattern matching in our language is limited to a single layer of enum variants. This limitation restricts the possibilities of pattern matching and makes it less useful for complex scenarios. In this article, we will explore the possibilities of allowing more complex pattern matching in our language.

Allow Matching on Primitives

One of the most basic and essential features of pattern matching is the ability to match on primitive types. Currently, our language only supports matching on enum variants, which is a very limited scope. We should allow matching on primitives such as numbers, booleans, and IP addresses.

Allow Matching on Numbers

Matching on numbers is a fundamental feature of pattern matching. It allows developers to write code that can handle different numerical values in a concise and expressive way. For example, we can use pattern matching to check if a number is within a certain range.

let x = 5;
match x {
    1..10 => println!("x is between 1 and 10"),
    _ => println!("x is not between 1 and 10"),
}

Allow Matching on Numeric and IP Addr Ranges

In addition to matching on single numbers, we should also allow matching on numeric and IP address ranges. This feature will enable developers to write code that can handle a range of values in a single pattern.

let ip = "192.168.1.1";
match ip {
    "192.168.1.0".."192.168.1.255" => println!("ip is in the range"),
    _ => println!("ip is not in the range"),
}

Allow Matching on Booleans

Matching on booleans is another essential feature of pattern matching. It allows developers to write code that can handle different boolean values in a concise and expressive way.

let x = true;
match x {
    true => println!("x is true"),
    false => println!("x is false"),
}

Allow Matching on IP Addresses

Matching on IP addresses is a fundamental feature of pattern matching. It allows developers to write code that can handle different IP addresses in a concise and expressive way.

let ip = "192.168.1.1";
match ip {
    "192.168.1.1" => println!("ip is 192.168.1.1"),
    _ => println!("ip is not 192.168.1.1"),
}

Allow Matching on Prefixes

Matching on prefixes is another essential feature of pattern matching. It allows developers to write code that can handle different prefixes in a concise and expressive way.

let prefix = "192.168.1.";
match prefix {
    "192.168.1." => println!("prefix is 192.168.1."),
    _ => println!("prefix is not 192.168.1."),
}

Allow or-Patterns

Another essential feature of pattern matching is the ability to use or-patterns. Or-patterns allow developers to specify multiple patterns that can match a value.

let x = 5;
match x {
    1 | 2 | 3 => println!("x is 1, 2, or 3"),
    _ => println!("x is not 1, 2, or 3"),
}

Allow Nested Patterns

Nested patterns are another essential feature of pattern matching. They allow developers to specify complex patterns that can match a value.

let x = (1, 2);
match x {
    (1, 2) => println!("x is (1, 2)"),
    _ => println!("x is not (1, 2)"),
}

Allow Constants

Constants are another essential feature of pattern matching. They allow developers to specify a value that can match a pattern.

let x = 5;
match x {
    5 => println!("x is 5"),
    _ => println!("x is not 5"),
}

Allow Matching on Records

Matching on records is another essential feature of pattern matching. It allows developers to specify a record that can match a value.

struct Person {
    name: String,
    age: i32,
}

let person = Person {
    name: "John".to_string(),
    age: 30,
};
match person {
    Person { name, age } => println!("name: {}, age: {}", name, age),
    _ => println!("not a person"),
}

Conclusion

Introduction

Pattern matching is a powerful feature in programming languages that allows developers to write more concise and expressive code. However, it can be a complex and nuanced topic, and many developers have questions about how it works and how to use it effectively. In this article, we will answer some of the most frequently asked questions about pattern matching.

Q: What is pattern matching?

A: Pattern matching is a feature in programming languages that allows developers to write code that can handle different values in a concise and expressive way. It is based on the idea of matching a value against a set of patterns, and executing a specific block of code when a match is found.

Q: What are the benefits of pattern matching?

A: The benefits of pattern matching include:

Concise code: Pattern matching allows developers to write code that is more concise and expressive than traditional if-else statements.
Improved readability: Pattern matching makes code easier to read and understand by clearly indicating the different values that a variable can take.
Reduced errors: Pattern matching reduces the likelihood of errors by making it easier to handle different values in a single block of code.

Q: What types of values can be matched with pattern matching?

A: Pattern matching can be used to match a wide range of values, including:

Primitives: Pattern matching can be used to match primitive values such as numbers, booleans, and characters.
Enums: Pattern matching can be used to match enum values.
Records: Pattern matching can be used to match records, which are composite values that consist of multiple fields.
Tuples: Pattern matching can be used to match tuples, which are composite values that consist of multiple values.

Q: How do I use pattern matching in my code?

A: To use pattern matching in your code, you will need to specify a set of patterns that can match a value. You can then use the match keyword to execute a specific block of code when a match is found.

let x = 5;
match x {
    1 => println!("x is 1"),
    2 => println!("x is 2"),
    3 => println!("x is 3"),
    _ => println!("x is not 1, 2, or 3"),
}

Q: What is the difference between pattern matching and if-else statements?

A: The main difference between pattern matching and if-else statements is that pattern matching is more concise and expressive. Pattern matching also makes it easier to handle different values in a single block of code.

Q: Can I use pattern matching with complex data structures?

A: Yes, pattern matching can be used with complex data structures such as records and tuples. You can use the match keyword to specify a set of patterns that can match a complex data structure.

struct Person {
    name: String,
    age: i32,
}

let person = Person {
    name: "John".to_string(),
    age: 30,
};
match person {
    Person { name, age } => println!("name: {}, age: {}", name, age),
    _ => println!("not a person"),
}

Q: Are there any limitations to pattern matching?

A: Yes, there are some limitations to pattern matching. For example, pattern matching can only be used with values that have a specific type. Additionally, pattern matching can be less efficient than traditional if-else statements for large numbers of values.

Conclusion

Pattern matching is a powerful feature in programming languages that allows developers to write more concise and expressive code. By understanding how pattern matching works and how to use it effectively, developers can write more efficient and maintainable code.