README
¶
nilo
Rusty Go Option library for handling nil values, some errors and marshaling
Caveats
- This library requires Go 1.23+
Intallation
go get -u github.com/javiorfo/nilo@latest
Example
Examples here
package main
import (
"errors"
"fmt"
"github.com/javiorfo/nilo"
)
type User struct {
Name string
}
// Implements nilo.Default interface
func (u User) Default() User {
return User{"Default Implementation"}
}
func main() {
var optUser = nilo.None[User]()
fmt.Printf("User or default: %+v\n", optUser.UnwrapOrDefault())
fmt.Printf("User or: %+v\n", optUser.UnwrapOr(*new(User)))
fmt.Printf("User or else: %+v\n", optUser.UnwrapOrElse(func() User { return User{"else"} }))
fmt.Printf("Map or: %+v\n", optUser.MapOr(User{"or"}, func(u User) User {
u.Name = "something"
return u
}))
nilo.FromResult(getUser(true)).OkAndResult(getUser2).Inspect(print)
_, err := test(false).OkOr(errors.New("some err"))
fmt.Println("Error:", err.Error())
fmt.Println(test(true).MapToString(func(v string) string { return v + ", World" }).UnwrapOr("another string"))
}
func test(b bool) nilo.Option[string] {
if b {
return nilo.Some("Hello")
}
return nilo.None[string]()
}
func print[T any](v *T) {
fmt.Printf("Value: %#v\n", *v)
}
func getUser(b bool) (*int, error) {
if b {
i := 1
return &i, nil
}
return nil, errors.New("error")
}
func getUser2(v *int) (*int, error) {
if *v == 0 {
return nil, errors.New("error")
}
i := *v + 2
return &i, nil
}
JSON marshal
package main
import (
"encoding/json"
"fmt"
"github.com/javiorfo/nilo"
)
type User struct {
Name string `json:"name"`
Code nilo.Option[string] `json:"code"`
}
func main() {
var unmarshalUser User
user := User{
Name: "Name",
Code: nilo.None[string](),
}
// Marshal
jsonData, err := json.MarshalIndent(user, "", " ")
if err != nil {
fmt.Println("Error marshaling to JSON:", err)
return
}
fmt.Println(string(jsonData))
// Unmarshal
err = json.Unmarshal(jsonData, &unmarshalUser)
if err != nil {
fmt.Println("Error unmarshaling:", err)
return
}
fmt.Printf("Unmarshaled User: %+v\n", unmarshalUser)
if unmarshalUser.Code.IsNone() {
fmt.Printf("Code is None: %s\n", unmarshalUser.Code)
}
// Put Some in Code
user.Code.Replace("some code")
// Marshal
jsonData, err = json.MarshalIndent(user, "", " ")
if err != nil {
fmt.Println("Error marshaling to JSON:", err)
return
}
fmt.Println(string(jsonData))
// Unmarshal
err = json.Unmarshal(jsonData, &unmarshalUser)
if err != nil {
fmt.Println("Error unmarshaling:", err)
return
}
fmt.Printf("Unmarshaled User: %+v\n", unmarshalUser)
if unmarshalUser.Code.IsSome() {
fmt.Printf("Code is Some with value: %s\n", unmarshalUser.Code.Unwrap())
}
}
All methods
func (o Option[T]) Unwrap() T
func (o Option[T]) UnwrapOr(other T) T
func (o Option[T]) UnwrapUnchecked() *T
func (o Option[T]) UnwrapOrDefault() T
func (o Option[T]) UnwrapOrElse(supplier func() T) T
func (o Option[T]) OkOr(err error) (*T, error)
func (o Option[T]) OkOrElse(err func() error) (*T, error)
func (o Option[T]) OrElse(supplier func() Option[T]) Option[T]
func (o Option[T]) Filter(filter func(T) bool) Option[T]
func (o Option[T]) IsNone() bool
func (o Option[T]) IsSome() bool
func (o Option[T]) Inspect(consumer func(T)) Option[T]
func (o Option[T]) InspectOrElse(consumer func(T), or func())
func None[T any]() Option[T]
func Some[T any](value T) Option[T]
func SomePtr[T any](value *T) Option[T]
func (o Option[T]) AndThen(fn func(T) Option[T]) Option[T]
func (o Option[T]) And(other Option[T]) Option[T]
func (o Option[T]) Or(other Option[T]) Option[T]
func (o Option[T]) Xor(other Option[T]) Option[T]
func (o Option[T]) IsSomeAnd(predicate func(T) bool) bool
func (o Option[T]) IsNoneOr(predicate func(T) bool) bool
func (o Option[T]) Expect(msg string) T
func (o *Option[T]) Take() Option[T]
func (o *Option[T]) TakeIf(predicate func(T) bool) Option[T]
func (o *Option[T]) Replace(value T) Option[T]
func (o *Option[T]) Insert(value T)
func (o *Option[T]) GetOrInsert(value T) T
func (o *Option[T]) GetOrInsertWith(supplier func() T)
func (o *Option[T]) GetOrInsertDefault() T
func (o Option[T]) Map(mapper func(T) T) Option[T]
func (o Option[T]) MapToAny(mapper func(T) any) Option[any]
func (o Option[T]) MapToString(mapper func(T) string) Option[string]
func (o Option[T]) MapToInt(mapper func(T) int) Option[int]
func (o Option[T]) MapToBool(mapper func(T) bool) Option[bool]
func (o Option[T]) MapOr(def T, mapper func(T) T) T
func (o Option[T]) MapOrAny(def any, mapper func(T) any) any
func (o Option[T]) MapOrString(def string, mapper func(T) string) string
func (o Option[T]) MapOrInt(def int, mapper func(T) int) int
func (o Option[T]) MapOrBool(def bool, mapper func(T) bool) bool
func (o Option[T]) MapOrElse(supplier func() T, mapper func(T) T) T
func (o Option[T]) MapOrElseAny(supplier func() any, mapper func(T) any) any
func (o Option[T]) MapOrElseString(supplier func() string, mapper func(T) string) string
func (o Option[T]) MapOrElseInt(supplier func() int, mapper func(T) int) int
func (o Option[T]) MapOrElseBool(supplier func() bool, mapper func(T) bool) bool
func (o Option[T]) MapOrDefault(mapper func(T) T) T
func (o Option[T]) OkAndResult(apply func(T) (T, error)) Option[T]
func FromResult[T any](value T, err error) Option[T]
func (o Option[T]) MarshalJSON() ([]byte, error)
func (o *Option[T]) UnmarshalJSON(data []byte) error
func (o Option[T]) String() string
Donate
Documentation
¶
Overview ¶
Package nilo provides a generic Option type that can be used to represent a value that may or may not be present.
Index ¶
- type Default
- type Option
- func (o Option[T]) And(other Option[T]) Option[T]
- func (o Option[T]) AndThen(fn func(T) Option[T]) Option[T]
- func (o Option[T]) Expect(msg string) T
- func (o Option[T]) Filter(filter func(T) bool) Option[T]
- func (o *Option[T]) GetOrInsert(value T) T
- func (o *Option[T]) GetOrInsertDefault() T
- func (o *Option[T]) GetOrInsertWith(supplier func() T) T
- func (o *Option[T]) Insert(value T)
- func (o Option[T]) Inspect(consumer func(T)) Option[T]
- func (o Option[T]) InspectOrElse(consumer func(T), or func())
- func (o Option[T]) IsNone() bool
- func (o Option[T]) IsNoneOr(predicate func(T) bool) bool
- func (o Option[T]) IsSome() bool
- func (o Option[T]) IsSomeAnd(predicate func(T) bool) bool
- func (o Option[T]) Map(mapper func(T) T) Option[T]
- func (o Option[T]) MapOr(def T, mapper func(T) T) T
- func (o Option[T]) MapOrAny(def any, mapper func(T) any) any
- func (o Option[T]) MapOrBool(def bool, mapper func(T) bool) bool
- func (o Option[T]) MapOrDefault(mapper func(T) T) T
- func (o Option[T]) MapOrElse(supplier func() T, mapper func(T) T) T
- func (o Option[T]) MapOrElseAny(supplier func() any, mapper func(T) any) any
- func (o Option[T]) MapOrElseBool(supplier func() bool, mapper func(T) bool) bool
- func (o Option[T]) MapOrElseInt(supplier func() int, mapper func(T) int) int
- func (o Option[T]) MapOrElseString(supplier func() string, mapper func(T) string) string
- func (o Option[T]) MapOrInt(def int, mapper func(T) int) int
- func (o Option[T]) MapOrString(def string, mapper func(T) string) string
- func (o Option[T]) MapToAny(mapper func(T) any) Option[any]
- func (o Option[T]) MapToBool(mapper func(T) bool) Option[bool]
- func (o Option[T]) MapToInt(mapper func(T) int) Option[int]
- func (o Option[T]) MapToString(mapper func(T) string) Option[string]
- func (o Option[T]) MarshalJSON() ([]byte, error)
- func (o Option[T]) OkAndResult(apply func(T) (T, error)) Option[T]
- func (o Option[T]) OkOr(err error) (*T, error)
- func (o Option[T]) OkOrElse(err func() error) (*T, error)
- func (o Option[T]) Or(other Option[T]) Option[T]
- func (o Option[T]) OrElse(supplier func() Option[T]) Option[T]
- func (o *Option[T]) Replace(value T) Option[T]
- func (o Option[T]) String() string
- func (o *Option[T]) Take() Option[T]
- func (o *Option[T]) TakeIf(predicate func(T) bool) Option[T]
- func (o *Option[T]) UnmarshalJSON(data []byte) error
- func (o Option[T]) Unwrap() T
- func (o Option[T]) UnwrapOr(other T) T
- func (o Option[T]) UnwrapOrDefault() T
- func (o Option[T]) UnwrapOrElse(supplier func() T) T
- func (o Option[T]) UnwrapUnchecked() *T
- func (o Option[T]) Xor(other Option[T]) Option[T]
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Default ¶ added in v1.1.0
type Default[T any] interface { Default() T }
Default is an interface that can be implemented by types that wish to provide a custom 'default' value. This is used by methods on `Option` such as `UnwrapOrDefault` or `GetOrInsertDefault` to create an instance of the type when a `None` `Option` is encountered.
Types that implement this interface can define their own logic for what constitutes a 'default' value, instead of relying on the Go language's zero value.
type Option ¶ added in v1.1.0
type Option[T any] struct { // contains filtered or unexported fields }
Option is a generic type that represents an option value. An `Option` can either be `Some`, containing a value of type `T`, or `None`, indicating the absence of a value.
func FromResult ¶ added in v1.1.0
FromResult creates an `Option` from a Go function's return values.
It returns a `Some` `Option` containing `value` if `err` is `nil`. If `err` is not `nil`, it returns a `None` `Option`. This is a convenient way to bridge error-handling patterns in Go with the `Option` type.
Parameters:
- value: The value to wrap in a `Some` `Option` if there is no error.
- err: The error returned from a function.
func SomePtr ¶ added in v1.1.0
SomePtr creates an Option from a pointer to a value. If the pointer is nil, it returns an empty Option.
func (Option[T]) And ¶ added in v1.1.0
And combines two `Option`s.
If both the current `Option` and the `other` `Option` are `Some`, it returns the `other` `Option`. In all other cases (if either `Option` is `None`), it returns `None`. This can be used to perform a logical "AND" operation on `Option` values.
Parameters:
- other: The other `Option` to combine with the current one.
func (Option[T]) AndThen ¶ added in v1.1.0
AndThen is a chaining method that applies a function to the contained value if the `Option` is `Some`, returning the result.
If the `Option` is `Some`, the `fn` is called with the unwrapped value, and the new `Option` returned by `fn` is the result. This allows for a sequence of fallible operations. If the `Option` is `None`, this method returns `None` without calling `fn`.
Parameters:
- fn: A function that takes the `Option`'s value and returns a new `Option`.
func (Option[T]) Expect ¶ added in v1.1.0
Expect returns the contained `Some` value, but panics with a custom message if the `Option` is `None`.
This method is used when a `None` value is considered an unrecoverable error in your program, and you want to crash with a descriptive message.
Parameters:
- msg: The message to be used in the panic if the `Option` is `None`.
func (Option[T]) Filter ¶ added in v1.1.0
Filter calls a predicate function on the contained value if the `Option` is `Some`.
If the `Option` is `Some` and the predicate returns `true`, it returns a `Some` `Option` with the original value. Otherwise, it returns a `None` `Option`. This is useful for removing values that do not meet a certain condition.
Parameters:
- filter: A predicate function that returns `true` or `false` based on the value.
func (*Option[T]) GetOrInsert ¶ added in v1.1.0
func (o *Option[T]) GetOrInsert(value T) T
GetOrInsert returns the contained value if the `Option` is `Some`. If the `Option` is `None`, it inserts the provided `value` into the `Option`, making it `Some`, and then returns the newly inserted value.
Parameters:
- value: The value to insert if the `Option` is `None`.
func (*Option[T]) GetOrInsertDefault ¶ added in v1.1.0
func (o *Option[T]) GetOrInsertDefault() T
GetOrInsertDefault returns the contained value if the `Option` is `Some`. If the `Option` is `None`, it inserts a default value, making it `Some`, and then returns the new value.
The default value is determined by the following:
- If the type `T` implements the `Default` interface, its `Default()` method is called to get the value.
- Otherwise, the Go language's zero value for type `T` is used.
func (*Option[T]) GetOrInsertWith ¶ added in v1.1.0
func (o *Option[T]) GetOrInsertWith(supplier func() T) T
GetOrInsertWith returns the contained value if the `Option` is `Some`. If the `Option` is `None`, it calls the `supplier` function, inserts the returned value into the `Option`, and then returns the new value.
This method is useful for providing a default value that is expensive to compute, as the `supplier` function is only called when needed.
Parameters:
- supplier: A function that provides the value to be inserted if the `Option` is `None`.
func (*Option[T]) Insert ¶ added in v1.1.0
func (o *Option[T]) Insert(value T)
Insert replaces the contained value with a new one.
If the `Option` is currently `None`, it is changed to `Some` with the new value. If the `Option` is already `Some`, its existing value is replaced by the new one.
Parameters:
- value: The new value to be inserted into the `Option`.
func (Option[T]) Inspect ¶ added in v1.1.0
Inspect calls a function on the contained value if the `Option` is `Some`, and then returns the original `Option`.
This is useful for debugging or logging the value without consuming the `Option`.
Parameters:
- consumer: A function that takes the `Option`'s value.
func (Option[T]) InspectOrElse ¶ added in v1.1.0
func (o Option[T]) InspectOrElse(consumer func(T), or func())
InspectOrElse calls one of two functions depending on whether the `Option` is `Some` or `None`.
If the `Option` is `Some`, it calls the `consumer` function with the contained value. If the `Option` is `None`, it calls the `or` function. This is useful for debugging or performing side effects based on the `Option`'s state.
Parameters:
- consumer: A function that takes the `Option`'s value, called if the `Option` is `Some`.
- or: A function with no parameters, called if the `Option` is `None`.
func (Option[T]) IsNoneOr ¶ added in v1.1.0
IsNoneOr returns `true` if the `Option` is `None` or if the contained value satisfies the given `predicate`.
This acts as a logical "OR" on the state of the `Option`. If the `Option` is `None`, the predicate is not evaluated, and `true` is returned. If it is `Some`, the function returns the result of the `predicate`.
Parameters:
- predicate: A function that takes the `Option`'s value and returns a boolean.
func (Option[T]) IsSomeAnd ¶ added in v1.1.0
IsSomeAnd returns `true` if the `Option` is `Some` and the value contained within it satisfies the given `predicate`.
If the `Option` is `None`, this method short-circuits and returns `false`. This is a convenient way to check for both presence and a condition in one call.
Parameters:
- predicate: A function that takes the `Option`'s value and returns a boolean.
func (Option[T]) Map ¶ added in v1.1.0
Map applies a function to the contained value of an Option if it is `Some` and returns a new `Option` containing the mapped value.
If the original `Option` is `None`, this method returns `None`.
Parameters:
- mapper: The function to apply to the `Option`'s value. It takes a value of type `T` and returns a value of the same type `T`.
Returns:
- A new `Option[T]` containing the result of the mapping, or `None` if the original `Option` was `None`.
func (Option[T]) MapOr ¶ added in v1.1.0
func (o Option[T]) MapOr(def T, mapper func(T) T) T
MapOr maps the `Option`'s value if it is `Some` and returns the result, otherwise returns a default value.
Parameters:
- def: The default value to return if the `Option` is `None`.
- mapper: A function to apply to the `Option`'s value if it is `Some`.
func (Option[T]) MapOrAny ¶ added in v1.2.0
MapOrAny maps the `Option`'s value to a string if it is `Some` and returns the result, otherwise returns a default any.
Parameters:
- def: The default any to return if the `Option` is `None`.
- mapper: A function to apply to the `Option`'s value to produce an any.
func (Option[T]) MapOrBool ¶ added in v1.1.0
MapOrBool maps the `Option`'s value to a boolean if it is `Some` and returns the result, otherwise returns a default boolean.
Parameters:
- def: The default boolean to return if the `Option` is `None`.
- mapper: A function to apply to the `Option`'s value to produce a boolean.
func (Option[T]) MapOrDefault ¶ added in v1.1.0
func (o Option[T]) MapOrDefault(mapper func(T) T) T
MapOrDefault maps the `Option`'s value if it is `Some`, otherwise returns the zero value of the type.
Parameters:
- mapper: A function to apply to the `Option`'s value if it is `Some`.
func (Option[T]) MapOrElse ¶ added in v1.1.0
func (o Option[T]) MapOrElse(supplier func() T, mapper func(T) T) T
MapOrElse maps the `Option`'s value if it is `Some` and returns the result, otherwise calls a supplier function to get the default value.
Parameters:
the function signature). - supplier: A function that provides the default value if the `Option` is `None`. - mapper: A function to apply to the `Option`'s value if it is `Some`.
func (Option[T]) MapOrElseAny ¶ added in v1.2.0
MapOrElseAny maps the `Option`'s value to an any if it is `Some`, otherwise calls a supplier function to get the default any.
Parameters:
the function signature). - supplier: A function that provides the default any if the `Option` is `None`. - mapper: A function to apply to the `Option`'s value to produce an any.
func (Option[T]) MapOrElseBool ¶ added in v1.1.0
MapOrElseBool maps the `Option`'s value to a boolean if it is `Some`, otherwise calls a supplier function to get the default boolean.
Parameters:
the function signature). - supplier: A function that provides the default boolean if the `Option` is `None`. - mapper: A function to apply to the `Option`'s value to produce a boolean.
func (Option[T]) MapOrElseInt ¶ added in v1.1.0
MapOrElseInt maps the `Option`'s value to an integer if it is `Some`, otherwise calls a supplier function to get the default integer.
Parameters:
the function signature). - supplier: A function that provides the default integer if the `Option` is `None`. - mapper: A function to apply to the `Option`'s value to produce an integer.
func (Option[T]) MapOrElseString ¶ added in v1.1.0
MapOrElseString maps the `Option`'s value to a string if it is `Some`, otherwise calls a supplier function to get the default string.
Parameters:
the function signature). - supplier: A function that provides the default string if the `Option` is `None`. - mapper: A function to apply to the `Option`'s value to produce a string.
func (Option[T]) MapOrInt ¶ added in v1.1.0
MapOrInt maps the `Option`'s value to an integer if it is `Some` and returns the result, otherwise returns a default integer.
Parameters:
- def: The default integer to return if the `Option` is `None`.
- mapper: A function to apply to the `Option`'s value to produce an integer.
func (Option[T]) MapOrString ¶ added in v1.1.0
MapOrString maps the `Option`'s value to a string if it is `Some` and returns the result, otherwise returns a default string.
Parameters:
- def: The default string to return if the `Option` is `None`.
- mapper: A function to apply to the `Option`'s value to produce a string.
func (Option[T]) MapToAny ¶ added in v1.2.0
MapToAny maps the contained value of an `Option[T]` to an any if it is `Some`, and returns a new `Option[any]` with the result.
If the original `Option` is `None`, this method returns `None[any]`.
Parameters:
- mapper: The function to apply to the `Option`'s value. It takes a value of type `T` and returns an `any`.
Returns:
- A new `Option[any]` containing the mapped value, or `None[any]` if the original `Option` was `None`.
func (Option[T]) MapToBool ¶ added in v1.1.0
MapToBool maps the contained value of an `Option[T]` to a boolean if it is `Some`, and returns a new `Option[bool]` with the result.
If the original `Option` is `None`, this method returns `None[bool]`.
Parameters:
- mapper: The function to apply to the `Option`'s value. It takes a value of type `T` and returns a `bool`.
Returns:
- A new `Option[bool]` containing the mapped value, or `None[bool]` if the original `Option` was `None`.
func (Option[T]) MapToInt ¶ added in v1.1.0
MapToInt maps the contained value of an `Option[T]` to an integer if it is `Some`, and returns a new `Option[int]` with the result.
If the original `Option` is `None`, this method returns `None[int]`.
Parameters:
- mapper: The function to apply to the `Option`'s value. It takes a value of type `T` and returns an `int`.
Returns:
- A new `Option[int]` containing the mapped value, or `None[int]` if the original `Option` was `None`.
func (Option[T]) MapToString ¶ added in v1.1.0
MapToString maps the contained value of an `Option[T]` to a string if it is `Some`, and returns a new `Option[string]` with the result.
If the original `Option` is `None`, this method returns `None[string]`.
Parameters:
- mapper: The function to apply to the `Option`'s value. It takes a value of type `T` and returns a `string`.
Returns:
- A new `Option[string]` containing the mapped value, or `None[string]` if the original `Option` was `None`.
func (Option[T]) MarshalJSON ¶ added in v1.1.0
MarshalJSON implements the `json.Marshaler` interface for `Option`.
If the `Option` is `None`, it marshals to the JSON value `null`. If the `Option` is `Some`, it marshals the wrapped value to its JSON representation.
func (Option[T]) OkAndResult ¶ added in v1.1.0
OkAndResult applies a function that returns a value and an error to the `Option`'s contained value.
If the `Option` is `Some` and the applied function returns a `nil` error, this method returns a `Some` `Option` with the function's returned value. In all other cases (if the `Option` is `None` or the function returns a non-nil error), it returns a `None` `Option`. This is useful for chaining operations that might fail.
Parameters:
- apply: A function that takes the `Option`'s value and returns a new value and an error.
func (Option[T]) OkOr ¶ added in v1.1.0
OkOr converts an `Option` into a Go-style `(value, error)` tuple.
If the `Option` is `Some`, it returns a pointer to the value and a `nil` error. If the `Option` is `None`, it returns a `nil` pointer and the provided `err`. This is useful for integrating `Option` with functions that return an error.
Parameters:
- err: The error to return if the `Option` is `None`.
func (Option[T]) OkOrElse ¶ added in v1.1.0
OkOrElse converts an `Option` into a `(value, error)` tuple.
If the `Option` is `Some`, it returns a pointer to the value and a `nil` error. If the `Option` is `None`, it returns a `nil` pointer and the error returned by the `err` supplier function. This is useful when creating the error is an expensive operation, as the supplier function is only called when needed.
Parameters:
- err: A function that returns the error to be used if the `Option` is `None`.
func (Option[T]) Or ¶ added in v1.1.0
Or returns the `Option` if it is `Some`, otherwise it returns the `other` `Option`.
This method acts as a logical "OR" operation. If the current `Option` is `Some`, its value is preferred. If it's `None`, it falls back to the `other` `Option`.
Parameters:
- other: The alternative `Option` to return if the current one is `None`.
func (Option[T]) OrElse ¶ added in v1.1.0
OrElse returns the `Option` itself if it is `Some`. If the `Option` is `None`, it calls the `supplier` function and returns the resulting `Option`.
This is useful for providing a fallback `Option` to use if the original is empty. The `supplier` function is only called if the `Option` is `None`, which can be beneficial for performance if creating the fallback is an expensive operation.
Parameters:
- supplier: A function that provides the fallback `Option` to return if the original `Option` is `None`.
func (*Option[T]) Replace ¶ added in v1.1.0
Replace replaces the contained value with a new value and returns the old `Option`.
If the `Option` is `Some`, its value is updated to `value`. The original `Some` `Option` with the old value is returned. If the `Option` is `None`, it remains `None`, and a new `Some` `Option` with the new value is returned.
Parameters:
- value: The new value to place into the `Option`.
func (Option[T]) String ¶ added in v1.1.0
String implements the `fmt.Stringer` interface for `Option`.
It returns a string representation of the `Option`. For `Some` `Option`s, the format is "Some(value)". For a `None` `Option`, the format is "None".
func (*Option[T]) Take ¶ added in v1.1.0
Take takes the value out of the `Option`, leaving a `None` in its place.
If the `Option` is `Some`, this method returns the original `Some` `Option` and sets the receiver to `None`. If the `Option` is `None`, it remains `None`.
func (*Option[T]) TakeIf ¶ added in v1.1.0
TakeIf takes the value out of the `Option` and leaves a `None` if the contained value satisfies the given `predicate`.
If the `Option` is `Some` and the `predicate` returns `true`, it behaves identically to `Take`, returning the original `Some` `Option` and setting the receiver to `None`. Otherwise, it returns `None` and does not modify the original `Option`.
Parameters:
- predicate: A function that tests the `Option`'s value.
func (*Option[T]) UnmarshalJSON ¶ added in v1.1.0
UnmarshalJSON implements the `json.Unmarshaler` interface for `Option`.
If the JSON data is `null`, it unmarshals into a `None` `Option`. Otherwise, it unmarshals the data into the `Option`'s value, creating a `Some` `Option` with the unmarshaled content.
func (Option[T]) Unwrap ¶ added in v1.1.0
func (o Option[T]) Unwrap() T
Unwrap returns the contained value of a `Some` `Option`.
Panics if the `Option` is `None`. This method should only be used when you are certain the `Option` contains a value.
func (Option[T]) UnwrapOr ¶ added in v1.1.0
func (o Option[T]) UnwrapOr(other T) T
UnwrapOr returns the contained value if the `Option` is `Some`, otherwise returns the provided default value `other`.
This is a safe alternative to `Unwrap` when you have a default value to use.
Parameters:
- other: The default value to return if the `Option` is `None`.
func (Option[T]) UnwrapOrDefault ¶ added in v1.1.0
func (o Option[T]) UnwrapOrDefault() T
UnwrapOrDefault returns the contained value if the `Option` is `Some`. If the `Option` is `None`, it returns a default value.
The default value is determined by the following:
- If the type `T` implements the `Default` interface, `Default()` is called to get the default value.
- Otherwise, the Go language's zero value for type `T` is returned.
func (Option[T]) UnwrapOrElse ¶ added in v1.1.0
func (o Option[T]) UnwrapOrElse(supplier func() T) T
UnwrapOrElse returns the contained value if the `Option` is `Some`, otherwise it calls the provided `supplier` function to get a default value.
This is useful for providing a default value that is expensive to compute, as the supplier function is only called when needed.
Parameters:
- supplier: A function that returns the default value if the `Option` is `None`.
func (Option[T]) UnwrapUnchecked ¶ added in v1.1.0
func (o Option[T]) UnwrapUnchecked() *T
UnwrapUnchecked returns a pointer to the contained value without checking if the `Option` is `Some`.
The caller is responsible for ensuring the `Option` is `Some` before calling this method. Calling this on a `None` `Option` will result in a nil pointer.
func (Option[T]) Xor ¶ added in v1.1.0
Xor returns the `Option` that is `Some`, if exactly one of them is `Some`.
This performs a logical "XOR" (exclusive OR) operation. It returns a `Some` `Option` only if either the current `Option` is `Some` and the `other` is `None`, or vice versa. If both are `Some` or both are `None`, it returns `None`.
Parameters:
- other: The other `Option` to perform the XOR operation with.
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