Swift Q & A


How do I create and use custom operators in Swift?

Creating and using custom operators in Swift can be a powerful tool to make your code more concise and expressive. While it should be used sparingly and thoughtfully, it can help improve the readability of your code when done right.


To create a custom operator in Swift, you need to specify its precedence and associativity, and then define its behavior using operator functions. Here’s a step-by-step guide on how to create and use custom operators:


  1. Choose a Symbol: Custom operators in Swift are defined using a combination of symbols, such as “+”, “-“, “*”, etc. Choose a symbol that makes sense for the operation you want to perform.


  1. Define Operator Functions: You need to define two functions for your custom operator: one for infix operators (binary operators) and one for prefix or postfix operators (unary operators). These functions should be declared using the `static func` keyword within a type. For example:
// Infix operator function
static func <~> (left: MyClass, right: MyClass) -> MyClass {
    // Define the behavior of the operator
    // You can perform any custom logic here

   Here, `<~>` is the custom operator symbol, and `MyClass` is the type on which this operator will be defined.


  1. Declare Operator: To make your custom operator available for use, you need to declare it at a global scope. This is typically done at the top level of a Swift file.


  infix operator <~>: AdditionPrecedence

   In this example, we’ve declared the `<~>` operator with a precedence level of `AdditionPrecedence`. You can choose the appropriate precedence group based on your operator’s behavior.


  1. Implement the Behavior: Inside your operator functions, implement the behavior that corresponds to your custom operator. You can perform any custom logic, calculations, or transformations based on the input parameters.


  1. Usage: You can now use your custom operator in your code, just like any built-in operator.
let result = object1 <~> object2

Remember that custom operators should be used judiciously and only when they enhance code readability and maintainability. Overusing custom operators can make your code less understandable to others, so it’s important to strike a balance between expressiveness and clarity. Additionally, documenting the purpose and behavior of your custom operators is essential for making your codebase more accessible to collaborators.


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Experienced iOS Engineer with 7+ years mastering Swift. Created fintech solutions, enhanced biopharma apps, and transformed retail experiences.