doc: improve documentation

The struct of the error is no longer exported.

It helps to provide a better documentation, even if it's a breaking change.

conversion.go

@@ -1,8 +1,3 @@
-// Package go-safecast solves the type conversion issues in Go
-//
-// In Go, integer type conversion can lead to unexpected behavior and errors if not handled carefully.
-// Issues can happen when converting between signed and unsigned integers, or when converting to a smaller integer type.
-
 package safecast
 
 import (
@@ -61,7 +56,7 @@ func Convert[NumOut Number](orig any) (converted NumOut, err error) {
 		return convertFromString[NumOut](v)
 	}
 
-	return 0, Error{
+	return 0, errorHelper{
 		err: fmt.Errorf("%w from %T", ErrUnsupportedConversion, orig),
 	}
 }
@@ -97,7 +92,7 @@ func convertFromNumber[NumOut Number, NumIn Number](orig NumIn) (converted NumOu
 			errBoundary = ErrExceedMinimumValue
 		}
 
-		return 0, Error{
+		return 0, errorHelper{
 			value:    orig,
 			err:      errBoundary,
 			boundary: boundary,
@@ -112,7 +107,7 @@ func convertFromNumber[NumOut Number, NumIn Number](orig NumIn) (converted NumOu
 	}
 
 	if !sameSign(orig, converted) {
-		return 0, Error{
+		return 0, errorHelper{
 			value:    orig,
 			err:      errBoundary,
 			boundary: boundary,
@@ -135,7 +130,7 @@ func convertFromNumber[NumOut Number, NumIn Number](orig NumIn) (converted NumOu
 		return converted, nil
 	}
 
-	return 0, Error{
+	return 0, errorHelper{
 		value:    orig,
 		err:      errBoundary,
 		boundary: boundary,
@@ -155,7 +150,7 @@ func convertFromString[NumOut Number](s string) (converted NumOut, err error) {
 	if strings.Contains(s, ".") {
 		o, err := strconv.ParseFloat(s, 64)
 		if err != nil {
-			return 0, Error{
+			return 0, errorHelper{
 				value: s,
 				err:   fmt.Errorf("%w %v to %T", ErrStringConversion, s, converted),
 			}
@@ -167,13 +162,13 @@ func convertFromString[NumOut Number](s string) (converted NumOut, err error) {
 		o, err := strconv.ParseInt(s, 0, 64)
 		if err != nil {
 			if errors.Is(err, strconv.ErrRange) {
-				return 0, Error{
+				return 0, errorHelper{
 					value:    s,
 					err:      ErrExceedMinimumValue,
 					boundary: math.MinInt,
 				}
 			}
-			return 0, Error{
+			return 0, errorHelper{
 				value: s,
 				err:   fmt.Errorf("%w %v to %T", ErrStringConversion, s, converted),
 			}
@@ -185,14 +180,14 @@ func convertFromString[NumOut Number](s string) (converted NumOut, err error) {
 	o, err := strconv.ParseUint(s, 0, 64)
 	if err != nil {
 		if errors.Is(err, strconv.ErrRange) {
-			return 0, Error{
+			return 0, errorHelper{
 				value:    s,
 				err:      ErrExceedMaximumValue,
 				boundary: uint(math.MaxUint),
 			}
 		}
 
-		return 0, Error{
+		return 0, errorHelper{
 			value: s,
 			err:   fmt.Errorf("%w %v to %T", ErrStringConversion, s, converted),
 		}

doc.go

@@ -0,0 +1,6 @@
+package safecast
+
+// Package go-safecast solves the type conversion issues in Go
+//
+// In Go, integer type conversion can lead to unexpected behavior and errors if not handled carefully.
+// Issues can happen when converting between signed and unsigned integers, or when converting to a smaller integer type.

errors.go

@@ -5,22 +5,34 @@ import (
 	"fmt"
 )
 
-var (
-	ErrConversionIssue       = errors.New("conversion issue")
-	ErrRangeOverflow         = errors.New("range overflow")
-	ErrExceedMaximumValue    = errors.New("maximum value for this type exceeded")
-	ErrExceedMinimumValue    = errors.New("minimum value for this type exceeded")
-	ErrUnsupportedConversion = errors.New("unsupported type")
-	ErrStringConversion      = errors.New("cannot convert from string")
-)
+// ErrConversionIssue is a generic error for type conversion issues
+// It is used to wrap other errors
+var ErrConversionIssue = errors.New("conversion issue")
+
+// ErrRangeOverflow is an error for when the value is outside the range of the desired type
+var ErrRangeOverflow = errors.New("range overflow")
+
+// ErrExceedMaximumValue is an error for when the value is greater than the maximum value of the desired type.
+var ErrExceedMaximumValue = errors.New("maximum value for this type exceeded")
+
+// ErrExceedMaximumValue is an error for when the value is less than the minimum value of the desired type.
+var ErrExceedMinimumValue = errors.New("minimum value for this type exceeded")
+
+// ErrUnsupportedConversion is an error for when the conversion is not supported from the provided type.
+var ErrUnsupportedConversion = errors.New("unsupported type")
+
+// ErrStringConversion is an error for when the conversion fails from string.
+var ErrStringConversion = errors.New("cannot convert from string")
 
-type Error struct {
+// errorHelper is a helper struct for error messages
+// It is used to wrap other errors, and provides additional information
+type errorHelper struct {
 	value    any
 	boundary any
 	err      error
 }
 
-func (e Error) Error() string {
+func (e errorHelper) Error() string {
 	errMessage := ErrConversionIssue.Error()
 
 	switch {
@@ -36,7 +48,7 @@ func (e Error) Error() string {
 	return errMessage
 }
 
-func (e Error) Unwrap() []error {
+func (e errorHelper) Unwrap() []error {
 	errs := []error{ErrConversionIssue}
 	if e.err != nil {
 		switch {