Refactor getting field name

checker/types.go

@@ -216,7 +216,7 @@ func fetchType(t reflect.Type, name string) (reflect.Type, bool) {
 			for i := 0; i < t.NumField(); i++ {
 				f := t.Field(i)
 				// Search all fields, even embedded structs.
-				if fieldName(f) == name {
+				if FieldName(f) == name {
 					return f.Type, true
 				}
 			}
@@ -290,7 +290,7 @@ func setTypeForIntegers(node ast.Node, t reflect.Type) {
 	}
 }
 
-func fieldName(field reflect.StructField) string {
+func FieldName(field reflect.StructField) string {
 	if taggedName := field.Tag.Get("expr"); taggedName != "" {
 		return taggedName
 	}

conf/types_table.go

@@ -1,6 +1,7 @@
 package conf
 
 import (
+	"github.com/antonmedv/expr/checker"
 	"reflect"
 )
 
@@ -84,7 +85,7 @@ func FieldsFromStruct(t reflect.Type) TypesTable {
 				}
 			}
 
-			types[actualFieldName(f)] = Tag{Type: f.Type}
+			types[checker.FieldName(f)] = Tag{Type: f.Type}
 		}
 	}
 
@@ -100,11 +101,3 @@ func dereference(t reflect.Type) reflect.Type {
 	}
 	return t
 }
-
-func actualFieldName(f reflect.StructField) string {
-	if taggedName := f.Tag.Get("expr"); taggedName != "" {
-		return taggedName
-	}
-
-	return f.Name
-}

vm/runtime/runtime.go

@@ -63,8 +63,14 @@ func Fetch(from, i interface{}) interface{} {
 		}
 
 	case reflect.Struct:
-		fieldName := reflect.ValueOf(i).String()
-		value := v.FieldByName(fieldName)
+		fieldName := i.(string)
+		value := v.FieldByNameFunc(func(name string) bool {
+			field, _ := v.Type().FieldByName(name)
+			if field.Tag.Get("expr") == fieldName {
+				return true
+			}
+			return name == fieldName
+		})
 		if value.IsValid() && value.CanInterface() {
 			return value.Interface()
 		}