Added FormScanner custom scanner, updated Go version.

webutil/formscanner.go

@@ -8,9 +8,12 @@ import (
 
 var ErrUnsupportedType = errors.New("unsupported type")
 
+type FormScanFunc func(name string, val any) (bool, error)
+
 type FormScanner struct {
-	form url.Values
-	err  error
+	form     url.Values
+	err      error
+	scanFunc FormScanFunc
 }
 
 func NewFormScanner(form url.Values) *FormScanner {
@@ -22,6 +25,14 @@ 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 {
+			return s
+		}
+	}
+
 	switch v := val.(type) {
 	case *bool:
 		*v = s.form.Has(name)