types

README

Useful generic types for Go

I've found myself reimplementing some small types and patterns in a lot of my recent Go projects, so I thought I'd distill them into a single package.

Refer to the package docs for details.

Documentation

Overview

Package types contains a collection of types and functions that are useful in Go.

Index

• func Go[T any](f func() (T, error)) chan Result[T]
• type Option
  • func None[T any]() Option[T]
  • func Ptr[T any](ptr *T) Option[T]
  • func Some[T any](value T) Option[T]
  • func Zero[T comparable](value T) Option[T]
  • func (o Option[T]) Default(value T) T
  • func (o Option[T]) Get() (T, bool)
  • func (o Option[T]) GoString() string
  • func (o Option[T]) MarshalJSON() ([]byte, error)
  • func (o Option[T]) MustGet() T
  • func (o Option[T]) Ok() bool
  • func (o Option[T]) Ptr() *T
  • func (o *Option[T]) Scan(src any) error
  • func (o Option[T]) String() string
  • func (o *Option[T]) UnmarshalJSON(data []byte) error
  • func (o Option[T]) Value() (driver.Value, error)
• type Pair
  • func PairOf[T, U any](first T, second U) Pair[T, U]
  • func (p Pair[T, U]) Get() (T, U)
• type Result
  • func Err[T any](err error) Result[T]
  • func Errorf[T any](format string, args ...interface{}) Result[T]
  • func Ok[T any](value T) Result[T]
  • func Outcome[T any](value T, err error) Result[T]
  • func (r Result[T]) Default(value T) T
  • func (r Result[T]) Err() error
  • func (r Result[T]) Get() (T, bool)
  • func (r Result[T]) GoString() string
  • func (r Result[T]) MarshalJSON() ([]byte, error)
  • func (r Result[T]) String() string
  • func (r *Result[T]) UnmarshalJSON(data []byte) error
• type Triple
  • func TripleOf[T, U, V any](first T, second U, third V) Triple[T, U, V]
  • func (t Triple[T, U, V]) Get() (T, U, V)

Functions

func Go

func Go[T any](f func() (T, error)) chan Result[T]

Go runs a function in a goroutine and returns a channel that will receive the Result.

Types

type Option

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

An Option type is a type that can contain a value or nothing.

func None

func None[T any]() Option[T]

None returns an Option that contains nothing.

func Ptr

func Ptr[T any](ptr *T) Option[T]

Ptr returns an Option that returns None[T]() if the pointer is nil, otherwise the dereferenced pointer.

func Some

func Some[T any](value T) Option[T]

Some returns an Option that contains a value.

func Zero

func Zero[T comparable](value T) Option[T]

Zero returns an Option that returns None[T]() if the value is the zero value, otherwise the value.

func (Option[T]) Default

func (o Option[T]) Default(value T) T

Default returns the Option value if it is present, otherwise it returns the value passed.

func (Option[T]) Get

func (o Option[T]) Get() (T, bool)

Get returns the value and a boolean indicating if the Option contains a value.

func (Option[T]) GoString

func (o Option[T]) GoString() string

func (Option[T]) MarshalJSON

func (o Option[T]) MarshalJSON() ([]byte, error)

func (Option[T]) MustGet

func (o Option[T]) MustGet() T

MustGet returns the value. It panics if the Option contains nothing.

func (Option[T]) Ok

func (o Option[T]) Ok() bool

Ok returns true if the Option contains a value.

func (Option[T]) Ptr

func (o Option[T]) Ptr() *T

Ptr returns a pointer to the value if the Option contains a value, otherwise nil.

func (*Option[T]) Scan

func (o *Option[T]) Scan(src any) error

func (Option[T]) String

func (o Option[T]) String() string

func (*Option[T]) UnmarshalJSON

func (o *Option[T]) UnmarshalJSON(data []byte) error

func (Option[T]) Value

func (o Option[T]) Value() (driver.Value, error)

type Pair

type Pair[T, U any] struct {
	First  T
	Second U
}

func PairOf

func PairOf[T, U any](first T, second U) Pair[T, U]

func (Pair[T, U]) Get

func (p Pair[T, U]) Get() (T, U)

type Result

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

A Result type is a type that can contain an error or a value.

func Err

func Err[T any](err error) Result[T]

Err returns a Result that contains an error.

func Errorf

func Errorf[T any](format string, args ...interface{}) Result[T]

Errorf returns a Result that contains a formatted error.

func Ok

func Ok[T any](value T) Result[T]

Ok returns a Result that contains a value.

func Outcome

func Outcome[T any](value T, err error) Result[T]

Outcome returns a Result that contains a value or an error.

It can be used to convert a function that returns a value and an error into a Result.

func (Result[T]) Default

func (r Result[T]) Default(value T) T

Default returns the Result value if it is present, otherwise it returns the value passed.

func (Result[T]) Err

func (r Result[T]) Err() error

Err returns the error, if any.

func (Result[T]) Get

func (r Result[T]) Get() (T, bool)

Get returns the value and a boolean indicating whether the value is present.

func (Result[T]) GoString

func (r Result[T]) GoString() string

func (Result[T]) MarshalJSON

func (r Result[T]) MarshalJSON() ([]byte, error)

func (Result[T]) String

func (r Result[T]) String() string

func (*Result[T]) UnmarshalJSON

func (r *Result[T]) UnmarshalJSON(data []byte) error

type Triple

type Triple[T, U, V any] struct {
	First  T
	Second U
	Third  V
}

func TripleOf

func TripleOf[T, U, V any](first T, second U, third V) Triple[T, U, V]

func (Triple[T, U, V]) Get

func (t Triple[T, U, V]) Get() (T, U, V)