diff --git a/webutil/formscanner.go b/webutil/formscanner.go
index a115294..5345315 100644
--- a/webutil/formscanner.go
+++ b/webutil/formscanner.go
@@ -8,12 +8,17 @@ import (
 
 var ErrUnsupportedType = errors.New("unsupported type")
 
+// FormScanFunc is a custom form scanner that can be used to scan custom
+// types using the form scanner.
+//
+// It returns true if it recognizes the type of val, and an error if scanning
+// fails.
 type FormScanFunc func(name string, val any) (bool, error)
 
 type FormScanner struct {
 	form     url.Values
 	err      error
-	scanFunc FormScanFunc
+	ScanFunc FormScanFunc
 }
 
 func NewFormScanner(form url.Values) *FormScanner {
@@ -25,10 +30,9 @@ func (s *FormScanner) Scan(name string, val any) *FormScanner {
 		return s
 	}
 
-	if s.scanFunc != nil {
-		ok, err := s.scanFunc(name, val)
-		s.err = err
-		if ok || err != nil {
+	if s.ScanFunc != nil {
+		if ok, err := s.ScanFunc(name, val); ok {
+			s.err = err
 			return s
 		}
 	}