made it work but looking for another approach

Former-commit-id: e61c4573543c57b8d6d4ef2583e40f52c391402f

core/router/macro/interpreter/ast/ast.go

@@ -51,21 +51,14 @@ const (
 	ParamTypePath
 )
 
-// ValidKind will return true if at least one param type is supported
-// for this std kind.
-func ValidKind(k reflect.Kind) bool {
-	switch k {
-	case reflect.String:
-		fallthrough
-	case reflect.Int:
-		fallthrough
-	case reflect.Int64:
-		fallthrough
-	case reflect.Bool:
-		return true
-	default:
-		return false
+func (pt ParamType) String() string {
+	for k, v := range paramTypes {
+		if v == pt {
+			return k
+		}
 	}
+
+	return "unexpected"
 }
 
 // Not because for a single reason
@@ -96,6 +89,23 @@ func (pt ParamType) Kind() reflect.Kind {
 	return reflect.Invalid // 0
 }
 
+// ValidKind will return true if at least one param type is supported
+// for this std kind.
+func ValidKind(k reflect.Kind) bool {
+	switch k {
+	case reflect.String:
+		fallthrough
+	case reflect.Int:
+		fallthrough
+	case reflect.Int64:
+		fallthrough
+	case reflect.Bool:
+		return true
+	default:
+		return false
+	}
+}
+
 // Assignable returns true if the "k" standard type
 // is assignabled to this ParamType.
 func (pt ParamType) Assignable(k reflect.Kind) bool {
@@ -133,6 +143,30 @@ func LookupParamType(ident string) ParamType {
 	return ParamTypeUnExpected
 }
 
+// LookupParamTypeFromStd accepts the string representation of a standard go type.
+// It returns a ParamType, but it may differs for example
+// the alphabetical, file, path and string are all string go types, so
+// make sure that caller resolves these types before this call.
+//
+// string matches to string
+// int matches to int
+// int64 matches to long
+// bool matches to boolean
+func LookupParamTypeFromStd(goType string) ParamType {
+	switch goType {
+	case "string":
+		return ParamTypeString
+	case "int":
+		return ParamTypeInt
+	case "int64":
+		return ParamTypeLong
+	case "bool":
+		return ParamTypeBoolean
+	default:
+		return ParamTypeUnExpected
+	}
+}
+
 // ParamStatement is a struct
 // which holds all the necessary information about a macro parameter.
 // It holds its type (string, int, alphabetical, file, path),