refactor(typeutils)!: refactor to pointer receivers

typeutils/result.go

@@ -1,5 +1,11 @@
 package typeutils
 
+import (
+	"errors"
+
+	"github.com/lbatuska/goutils/assert"
+)
+
 // CTORS BEGIN
 func Ok[T any](value T) Result[T] {
 	return Result[T]{value: value, err: nil}
@@ -15,44 +21,68 @@ func Err_t[T any](err error, x T) Result[T] {
 
 // CTORS END
 
-func (res Result[T]) IsOk() bool  { return res.err == nil }
-func (res Result[T]) IsErr() bool { return res.err != nil }
+func (res *Result[T]) IsOk() bool {
+	if res == nil {
+		return false
+	}
+	return res.err == nil
+}
 
-func (res Result[T]) HasValue() bool { return res.IsOk() }
+func (res *Result[T]) IsErr() bool {
+	if res == nil {
+		return true
+	}
+	return res.err != nil
+}
+
+func (res *Result[T]) HasValue() bool {
+	if res == nil {
+		return false
+	}
+	return res.IsOk()
+}
 
 // UNWRAPPABLE INTERFACE
-func (res Result[T]) Expect(msg string) T {
+func (res *Result[T]) Expect(msg string) T {
+	assert.NotNil(res)
 	if res.err == nil {
 		return res.value
 	}
 	panic(msg)
 }
 
-func (res Result[T]) Unwrap() T {
+func (res *Result[T]) Unwrap() T {
+	assert.NotNil(res)
 	if res.err == nil {
 		return res.value
 	}
 	panic("Tried unwrapping a Result that had an error value!")
 }
 
-func (res Result[T]) UnwrapOr(val T) T {
-	if res.err == nil {
-		return res.value
+func (res *Result[T]) UnwrapOr(val T) T {
+	if res != nil {
+		if res.err == nil {
+			return res.value
+		}
 	}
 	return val
 }
 
-func (res Result[T]) UnwrapOrDefault() T {
-	if res.err == nil {
-		return res.value
+func (res *Result[T]) UnwrapOrDefault() T {
+	if res != nil {
+		if res.err == nil {
+			return res.value
+		}
 	}
 	var ret T
 	return ret
 }
 
-func (res Result[T]) UnwrapOrElse(f func() T) T {
-	if res.err == nil {
-		return res.value
+func (res *Result[T]) UnwrapOrElse(f func() T) T {
+	if res != nil {
+		if res.err == nil {
+			return res.value
+		}
 	}
 	return f()
 }
@@ -60,7 +90,11 @@ func (res Result[T]) UnwrapOrElse(f func() T) T {
 // UNWRAPPABLE INTERFACE
 
 // This function panic on Ok instead of Err
-func (res Result[T]) ExpectErr(msg string) error {
+func (res *Result[T]) ExpectErr(msg string) error {
+	if res == nil {
+		return errors.New("ExpectErr was called on a nil Result.")
+	}
+
 	if res.err != nil {
 		return res.err
 	}
@@ -68,7 +102,10 @@ func (res Result[T]) ExpectErr(msg string) error {
 }
 
 // This function panic on Ok instead of Err
-func (res Result[T]) UnwrapErr() error {
+func (res *Result[T]) UnwrapErr() error {
+	if res == nil {
+		return errors.New("UnwrapErr was called on a nil Result.")
+	}
 	if res.err != nil {
 		return res.err
 	}
@@ -76,15 +113,22 @@ func (res Result[T]) UnwrapErr() error {
 }
 
 // transforms Result into Option, mapping Ok(v) to Some(v) and Err(e) to None
-func (res Result[T]) Ok() Optional[T] {
-	if res.err == nil {
-		return Optional[T]{value: res.value, present: true}
+func (res *Result[T]) Ok() Optional[T] {
+	if res != nil {
+		if res.err == nil {
+			return Optional[T]{value: res.value, present: true}
+		}
 	}
 	return Optional[T]{present: false}
 }
 
 // transforms Result into Option, mapping Err(e) to Some(e) and Ok(v) to None
-func (res Result[T]) Err() Optional[error] {
+func (res *Result[T]) Err() Optional[error] {
+	if res == nil {
+		return Optional[error]{
+			value: errors.New("Err was called on a nil Result."), present: true,
+		}
+	}
 	if res.err != nil {
 		return Optional[error]{value: res.err, present: true}
 	}