optional

Documentation

Overview

Package optional provides a utility type for representing optional values, similar to the concept of Optionals in other programming languages like Java or Rust.

Index

• type Optional
  • func Empty[T any]() Optional[T]
  • func Of[T any](v T) Optional[T]
  • func (o Optional[T]) IsPresent() bool
  • func (o Optional[T]) Value() T

Types

type Optional

type Optional[T any] struct {
	// contains filtered or unexported fields
}

Optional represents a value that may or may not be present.

Type Parameters:

• T: The type of the value being wrapped.

Example:

optionalString := Of("hello")
if optionalString.IsPresent() {
    fmt.Println("Value:", optionalString.Value()) // Output: Value: hello
}

emptyOptional := Empty[int]()
fmt.Println("Is present:", emptyOptional.IsPresent()) // Output: Is present: false

func Empty

func Empty[T any]() Optional[T]

Empty creates an Optional with no value.

Returns:

• An empty Optional.

Example:

emptyOptional := Empty[string]() // Optional[string] with no value

func Of

func Of[T any](v T) Optional[T]

Of creates an Optional containing the provided value.

Parameters:

• v: The value to wrap in an Optional.

Returns:

• An Optional containing the provided value.

Example:

optionalInt := Of(42) // Optional[int] containing 42

func (Optional[T]) IsPresent

func (o Optional[T]) IsPresent() bool

IsPresent checks whether the Optional contains a value.

Returns:

• true if the Optional contains a value, false otherwise.

Example:

optionalString := Of("hello")
fmt.Println(optionalString.IsPresent()) // Output: true

emptyOptional := Empty[string]()
fmt.Println(emptyOptional.IsPresent()) // Output: false

func (Optional[T]) Value

func (o Optional[T]) Value() T

Value retrieves the value stored in the Optional.

Returns:

• The stored value if present.
• A zero value of type T if the Optional is empty.

Example:

optionalInt := Of(42)
fmt.Println(optionalInt.Value()) // Output: 42

emptyOptional := Empty[int]()
fmt.Println(emptyOptional.Value()) // Output: 0