Merge pull request #11 from manicar2093/feat/work-with-custom-types

feat: add new way to assign values on sql scan

goption.go

@@ -21,7 +21,8 @@ func Empty[T any]() Optional[T] {
 
 // Of returns an Optional with the specified present value. It does not matters if value is nil
 func Of[T any](value T) Optional[T] {
-	return Optional[T]{value: value, isValidValue: isValidData(value)}
+	_, isValid := isValidData(value)
+	return Optional[T]{value: value, isValidValue: isValid}
 }
 
 // Get when a value is present returns the value, otherwise throws ErrNoSuchElement.
@@ -62,20 +63,20 @@ func (c Optional[T]) MustGet() T {
 	return val
 }
 
-func isValidData[T any](value T) bool {
+func isValidData[T any](value T) (reflect.Value, bool) {
 	typeOfValue := reflect.TypeOf(value)
 	if typeOfValue == nil {
-		return false
+		return reflect.Value{}, false
 	}
-	kind := typeOfValue.Kind()
+
 	val := reflect.ValueOf(value)
 
-	switch kind {
+	switch typeOfValue.Kind() {
 	case reflect.Pointer:
-		return !val.IsNil()
+		return val, !val.IsNil()
 	case reflect.Slice:
-		return val.Len() != 0
+		return val, val.Len() != 0
 	default:
-		return !val.IsZero()
+		return val, !val.IsZero()
 	}
 }

sql.go

@@ -1,18 +1,22 @@
 package goption
 
-import "database/sql/driver"
+import (
+	"database/sql/driver"
+	"fmt"
+	"reflect"
+)
 
 // Scan assigns a value from a database driver.
 //
 // The src value will be of one of the following types:
 //
-//    int64
-//    float64
-//    bool
-//    []byte
-//    string
-//    time.Time
-//    nil - for NULL values
+//	int64
+//	float64
+//	bool
+//	[]byte
+//	string
+//	time.Time
+//	nil - for NULL values
 //
 // An error should be returned if the value cannot be stored
 // without loss of information.
@@ -21,10 +25,16 @@ import "database/sql/driver"
 // and should not be retained. Their underlying memory is owned by the driver.
 // If retention is necessary, copy their values before the next call to Scan.
 func (c *Optional[T]) Scan(src any) error {
-	isSrcValid := isValidData(src)
+	srcValue, isSrcValid := isValidData(src)
 	c.isValidValue = isSrcValid
 	if isSrcValid {
-		c.value = src.(T)
+		destType := reflect.TypeOf(c.value)
+		if !srcValue.Type().ConvertibleTo(destType) {
+			return fmt.Errorf("interface conversion: interface {} is %s, not %s", srcValue.Type(), destType)
+		}
+
+		c.value = srcValue.Convert(destType).Interface().(T)
+		return nil
 	}
 	return nil
 }

sql_test.go

@@ -133,6 +133,17 @@ var _ = Describe("Sql", func() {
 				Expect(opt.IsPresent()).To(BeFalse())
 			})
 		})
+
+		When("has a custom type", func() {
+			It("assign it by its type", func() {
+				type Money int
+
+				opt := goption.Empty[Money]()
+
+				Expect(opt.Scan(400)).To(Succeed())
+				Expect(opt.IsPresent()).To(BeTrue())
+			})
+		})
 	})
 
 	Describe("Value", func() {