pointer

README

pointer package

This package contains a set of helper functions for working with pointers.

Documentation

Index

• func From[V any](v V) *V
• func Optional[V comparable](v V) *V
• func Unwrap[V any](v *V) V

Examples

• From
• Optional
• Unwrap

Functions

func From

func From[V any](v V) *V

From returns pointer to the value

Example

// From empty string it returns pointer to empty string
ps0 := pointer.From("")
ps1 := pointer.From("Hello")
fmt.Printf("%v,%v\n", *ps0, *ps1)
pi := pointer.From(1)
fmt.Printf("%v\n", *pi)
pstr := pointer.From(point{0, 5})
fmt.Printf("%#v\n", pstr)

Output:
,Hello
1
&pointer_test.point{x:0, y:5}

func Optional

func Optional[V comparable](v V) *V

Optional returns the pointer to the value if the value is not zero, otherwise it returns nil

Example

// Optional pointer of zero is nil
pi0 := pointer.Optional(0)
pi1 := pointer.Optional(1)
fmt.Printf("%v %#v\n", pi0, *pi1)
// Same applies to the string
ps0 := pointer.Optional("")
ps1 := pointer.Optional("1")
fmt.Printf("%v %#v\n", ps0, *ps1)
// Same applies to the struct
pstr0 := pointer.Optional(point{})
pstr1 := pointer.Optional(point{1, 2})
fmt.Printf("%#v %#v\n", pstr0, pstr1)

// works for time as well
pt0 := pointer.Optional(time.Time{})
pt1 := pointer.Optional(time.Date(2022, 5, 22, 0, 0, 0, 0, time.UTC))
fmt.Printf("%#v %#v\n", pt0, pt1)

// Optional won't work for interfaces
// var any0 any
// any0 = point{}
// pany0 := pointer.Optional(any0)

Output:
<nil> 1
<nil> "1"
(*pointer_test.point)(nil) &pointer_test.point{x:1, y:2}
<nil> time.Date(2022, time.May, 22, 0, 0, 0, 0, time.UTC)

func Unwrap

func Unwrap[V any](v *V) V

Unwrap extracts value from the pointer if not nil, otherwise it returns zero value

Example

// Unwrapping integers works as expected
pi0 := new(int)
pi1 := pointer.From(1)
i0 := pointer.Unwrap(pi0)
i1 := pointer.Unwrap(pi1)
fmt.Printf("%v %v\n", i0, i1)

point0 := new(point)
point1 := &point{1, 5}
// Unwrapping <nil> results in 0 filled struct
pstr0 := pointer.Unwrap(point0)
pstr1 := pointer.Unwrap(point1)
fmt.Printf("%v %v\n", pstr0, pstr1)

Output:
0 1
(0,0) (1,5)