Add UnwrapOr* functions (#40)

Added `UnwrapOr`, `UnwrapOrElse` and `UnwrapOrDefault` functions to
`Option` & `Result` types.

Author: Dean Karn

CHANGELOG.md

@@ -6,6 +6,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [5.21.3] - 2023-10-18
+### Added
+ - `UnwrapOr`, `UnwrapOrElse` and `UnwrapOrDefault` functions to `Option` & `Result` types.
+
 ## [5.21.3] - 2023-10-11
 ### Fixed
 - Fix SQL Scanner interface not returning None for Option when source data is nil.
@@ -78,7 +82,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 - Added `timext.NanoTime` for fast low level monotonic time with nanosecond precision.
 
-[Unreleased]: https://github.com/go-playground/pkg/compare/v5.21.3...HEAD
+[Unreleased]: https://github.com/go-playground/pkg/compare/v5.22.0...HEAD
+[5.22.0]: https://github.com/go-playground/pkg/compare/v5.21.3..v5.22.0
 [5.21.3]: https://github.com/go-playground/pkg/compare/v5.21.2..v5.21.3
 [5.21.2]: https://github.com/go-playground/pkg/compare/v5.21.1..v5.21.2
 [5.21.1]: https://github.com/go-playground/pkg/compare/v5.21.0..v5.21.1

README.md

@@ -1,6 +1,6 @@
 # pkg
 
-![Project status](https://img.shields.io/badge/version-5.21.3-green.svg)
+![Project status](https://img.shields.io/badge/version-5.22.0-green.svg)
 [![Lint & Test](https://github.com/go-playground/pkg/actions/workflows/go.yml/badge.svg)](https://github.com/go-playground/pkg/actions/workflows/go.yml)
 [![Coverage Status](https://coveralls.io/repos/github/go-playground/pkg/badge.svg?branch=master)](https://coveralls.io/github/go-playground/pkg?branch=master)
 [![GoDoc](https://godoc.org/github.com/go-playground/pkg?status.svg)](https://pkg.go.dev/mod/github.com/go-playground/pkg/v5)

values/option/option.go

@@ -69,6 +69,30 @@ func (o Option[T]) Unwrap() T {
 	panic("Option.Unwrap: option is None")
 }
 
+// UnwrapOr returns the contained `Some` value or provided default value.
+//
+// Arguments passed to `UnwrapOr` are eagerly evaluated; if you are passing the result of a function call,
+// look to use `UnwrapOrElse`, which can be lazily evaluated.
+func (o Option[T]) UnwrapOr(value T) T {
+	if o.isSome {
+		return o.value
+	}
+	return value
+}
+
+// UnwrapOrElse returns the contained `Some` value or computes it from a provided function.
+func (o Option[T]) UnwrapOrElse(fn func() T) T {
+	if o.isSome {
+		return o.value
+	}
+	return fn()
+}
+
+// UnwrapOrDefault returns the contained `Some` value or the default value of the type T.
+func (o Option[T]) UnwrapOrDefault() T {
+	return o.value
+}
+
 // Some creates a new Option with the given values.
 func Some[T any](value T) Option[T] {
 	return Option[T]{value, true}

values/option/option_test.go

@@ -26,6 +26,37 @@ type testStructType struct {
 	Name string
 }
 
+func TestUnwraps(t *testing.T) {
+	none := None[int]()
+	PanicMatches(t, func() { none.Unwrap() }, "Option.Unwrap: option is None")
+
+	v := none.UnwrapOr(3)
+	Equal(t, 3, v)
+
+	v = none.UnwrapOrElse(func() int { return 2 })
+	Equal(t, 2, v)
+
+	v = none.UnwrapOrDefault()
+	Equal(t, 0, v)
+
+	// now test with a pointer type.
+	type myStruct struct {
+		S string
+	}
+
+	sNone := None[*myStruct]()
+	PanicMatches(t, func() { sNone.Unwrap() }, "Option.Unwrap: option is None")
+
+	v2 := sNone.UnwrapOr(&myStruct{S: "blah"})
+	Equal(t, &myStruct{S: "blah"}, v2)
+
+	v2 = sNone.UnwrapOrElse(func() *myStruct { return &myStruct{S: "blah 2"} })
+	Equal(t, &myStruct{S: "blah 2"}, v2)
+
+	v2 = sNone.UnwrapOrDefault()
+	Equal(t, nil, v2)
+}
+
 func TestSQLDriverValue(t *testing.T) {
 
 	var v valueTest

values/result/result.go

@@ -38,6 +38,30 @@ func (r Result[T, E]) Unwrap() T {
 	panic("Result.Unwrap(): result is Err")
 }
 
+// UnwrapOr returns the contained Ok value or a provided default.
+//
+// Arguments passed to UnwrapOr are eagerly evaluated; if you are passing the result of a function call,
+// look to use `UnwrapOrElse`, which can be lazily evaluated.
+func (r Result[T, E]) UnwrapOr(value T) T {
+	if r.isOk {
+		return r.ok
+	}
+	return value
+}
+
+// UnwrapOrElse returns the contained Ok value or computes it from a provided function.
+func (r Result[T, E]) UnwrapOrElse(fn func() T) T {
+	if r.isOk {
+		return r.ok
+	}
+	return fn()
+}
+
+// UnwrapOrDefault returns the contained Ok value or the default value of the type T.
+func (r Result[T, E]) UnwrapOrDefault() T {
+	return r.ok
+}
+
 // Err returns the error of the result. To be used after calling IsOK()
 func (r Result[T, E]) Err() E {
 	return r.err

values/result/result_test.go

@@ -5,13 +5,28 @@ package resultext
 
 import (
 	"errors"
+	"io"
 	"testing"
 
 	. "github.com/go-playground/assert/v2"
 )
 
 type myStruct struct{}
 
+func TestUnwrap(t *testing.T) {
+	er := Err[int, error](io.EOF)
+	PanicMatches(t, func() { er.Unwrap() }, "Result.Unwrap(): result is Err")
+
+	v := er.UnwrapOr(3)
+	Equal(t, 3, v)
+
+	v = er.UnwrapOrElse(func() int { return 2 })
+	Equal(t, 2, v)
+
+	v = er.UnwrapOrDefault()
+	Equal(t, 0, v)
+}
+
 func TestResult(t *testing.T) {
 	result := returnOk()
 	Equal(t, true, result.IsOk())