make experiment with simplified structs work

exp_test.go

@@ -0,0 +1,34 @@
+package iso8583_test
+
+import (
+	"testing"
+
+	"github.com/moov-io/iso8583"
+	"github.com/moov-io/iso8583/specs"
+	"github.com/stretchr/testify/require"
+)
+
+func TestStructWithTypes(t *testing.T) {
+	type authRequestData struct {
+		MTI                  string `index:"0"`
+		PrimaryAccountNumber string `index:"2"`
+		ProcessingCode       int    `index:"3"`
+	}
+
+	t.Run("pack", func(t *testing.T) {
+		authRequest := &authRequestData{
+			MTI:                  "0110",
+			PrimaryAccountNumber: "4242424242424242",
+			ProcessingCode:       200000,
+		}
+
+		message := iso8583.NewMessage(specs.Spec87ASCII)
+		err := message.Marshal(authRequest)
+		require.NoError(t, err)
+
+		packed, err := message.Pack()
+		require.NoError(t, err)
+
+		require.Equal(t, "011060000000000000000000000000000000164242424242424242200000", string(packed))
+	})
+}

field/numeric.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"reflect"
 	"strconv"
 
 	"github.com/moov-io/iso8583/utils"
@@ -143,6 +144,31 @@ func (f *Numeric) Unmarshal(v interface{}) error {
 }
 
 func (f *Numeric) SetData(data interface{}) error {
+	if v, ok := data.(reflect.Value); ok {
+		switch v.Kind() {
+		case reflect.Int:
+			f.value = int(v.Int())
+		case reflect.String:
+			val, err := strconv.Atoi(v.String())
+			if err != nil {
+				return utils.NewSafeError(err, "failed to convert into number")
+			}
+			f.value = val
+		default:
+			return fmt.Errorf("data does not match required *Numeric type")
+		}
+		return nil
+	}
+
+	// if v.Kind() == reflect.Int {
+	// }
+	// if v, ok := data.(reflect.Value); ok {
+	// 	if v.CanSet() {
+	// 		v.Set(reflect.ValueOf(f.value))
+	// 		return nil
+	// 	}
+	// }
+
 	if data == nil {
 		return nil
 	}

field/string.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"reflect"
 
 	"github.com/moov-io/iso8583/utils"
 )
@@ -129,6 +130,20 @@ func (f *String) Unmarshal(v interface{}) error {
 }
 
 func (f *String) SetData(data interface{}) error {
+	if v, ok := data.(reflect.Value); ok {
+		switch v.Kind() {
+		case reflect.String:
+			f.value = v.String()
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+			f.value = fmt.Sprintf("%d", v.Int())
+		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+			f.value = fmt.Sprintf("%d", v.Uint())
+		default:
+			return fmt.Errorf("unsupported type %v", v.Kind())
+		}
+		return nil
+	}
+
 	if data == nil {
 		return nil
 	}

message.go

@@ -376,7 +376,9 @@ func (m *Message) Marshal(v interface{}) error {
 			continue
 		}
 
-		err = messageField.Marshal(dataField.Interface())
+		err = messageField.Marshal(dataField)
+
+		// err = messageField.Marshal(dataField.Interface())
 		if err != nil {
 			return fmt.Errorf("failed to set value to field %d: %w", fieldIndex, err)
 		}